2.8 Integration in Maple

# 
# 
#                                                WORKSHEET#19
# 
#                                               Integration in Maple
# 
# 
# 
#                              
--------------------------------------------------------------------------------
> f:=1/(x^2+1);

                                           1
                                   f := ------
                                         2
                                        x  + 1
--------------------------------------------------------------------------------
> int(f,x);

                                    arctan(x)
--------------------------------------------------------------------------------
> diff(",x);

                                        1
                                     ------
                                      2
                                     x  + 1
--------------------------------------------------------------------------------
> Int(f,x);

                                    /
                                   |     1
                                   |  ------ dx
                                   |   2
                                  /   x  + 1
--------------------------------------------------------------------------------
> Int(f,x)=int(f,x);

                              /
                             |     1
                             |  ------ dx = arctan(x)
                             |   2
                            /   x  + 1
--------------------------------------------------------------------------------
> Int(f,x)=int(f,x)+c;

                            /
                           |     1
                           |  ------ dx = arctan(x) + c
                           |   2
                          /   x  + 1
--------------------------------------------------------------------------------
> f:=1/sqrt(x^2-1);

                                          1
                                f := -----------
                                       2     1/2
                                     (x  - 1)
--------------------------------------------------------------------------------
> int(f,x);

                                        2     1/2
                               ln(x + (x  - 1)   )
--------------------------------------------------------------------------------
> diff(",x);

                                          x
                                 1 + -----------
                                       2     1/2
                                     (x  - 1)
                                 ---------------
                                       2     1/2
                                 x + (x  - 1)
--------------------------------------------------------------------------------
> simplify(");

                                        1
                                   -----------
                                     2     1/2
                                   (x  - 1)
--------------------------------------------------------------------------------
> f:=sqrt(1-x^2);

                                           2 1/2
                                f := (1 - x )
--------------------------------------------------------------------------------
> int(f,x);

                                    2 1/2
                        1/2 x (1 - x )    + 1/2 arcsin(x)
--------------------------------------------------------------------------------
> diff(",x);

                                            2
                          2 1/2            x              1
                1/2 (1 - x )    - 1/2 ----------- + -------------
                                            2 1/2           2 1/2
                                      (1 - x )      2 (1 - x )
--------------------------------------------------------------------------------
> simplify(");

                                      2     1/2
                                  I (x  - 1)
--------------------------------------------------------------------------------
> simplify("-f);

                               2     1/2         2 1/2
                           I (x  - 1)    - (1 - x )
--------------------------------------------------------------------------------
> simplify(",symbolic);

                                        0
--------------------------------------------------------------------------------
> int(f,x=-1..1);

                                     1/2 Pi
--------------------------------------------------------------------------------
> int(f,x=1..2);

                            1/2
                         I 3    + 1/2 arcsin(2) - 1/4 Pi
--------------------------------------------------------------------------------
> evalf((1/2)*arcsin(2));

                           .7853981635 - .6584789485 I
--------------------------------------------------------------------------------
> evalf("");

                                  1.073571860 I
--------------------------------------------------------------------------------
> evalf(Pi/4);

                                   .7853981635
--------------------------------------------------------------------------------
> subs(x=2,f);

                                         1/2
                                     (-3)
--------------------------------------------------------------------------------
> evalf(");

                                  1.732050808 I
--------------------------------------------------------------------------------
> f:=1/sqrt(1-x^4);

                                          1
                                f := -----------
                                           4 1/2
                                     (1 - x )
--------------------------------------------------------------------------------
> int(f,x);\


                                 /
                                |       1
                                |  ----------- dx
                                |        4 1/2
                               /   (1 - x )
--------------------------------------------------------------------------------
> evalf(int(f,x=0..1));

                                   1.311028778
--------------------------------------------------------------------------------
> evalf(Int(f,x=0..1));

                                   1.311028777
--------------------------------------------------------------------------------
> Digits:=20:
--------------------------------------------------------------------------------
> evalf(int(f,x=0..1));

                              1.3110287771460599053
--------------------------------------------------------------------------------
> evalf(Int(f,x=0..1));

                              1.3110287771460599052
--------------------------------------------------------------------------------
> Digits:=10:
--------------------------------------------------------------------------------
> int(f,x=0..1);

                                        3/2  1/2
                                      Pi    2
                                 1/4 -----------
                                               2
                                     GAMMA(3/4)
--------------------------------------------------------------------------------
> evalf(");

                                   1.311028778
--------------------------------------------------------------------------------
> Int(f,x=0..1);

                                 1
                                 /
                                |       1
                                |  ----------- dx
                                |        4 1/2
                               /   (1 - x )
                               0
--------------------------------------------------------------------------------
> evalf(");

                                   1.311028777
--------------------------------------------------------------------------------
> f:=(x^2+x+1)/(x^4-1);\


                                       2
                                      x  + x + 1
                                 f := ----------
                                         4
                                        x  - 1
--------------------------------------------------------------------------------
> partialfrac(");

                                          2
                                         x  + x + 1
                             partialfrac(----------)
                                            4
                                           x  - 1
--------------------------------------------------------------------------------
> ?partialfrac
Try one of the following topics:


 {parse, parfrac, parametric, parity, parallel, parampass, parameter, partition}
--------------------------------------------------------------------------------
> parfrac(f);

                                        2
                                       x  + x + 1
                               parfrac(----------)
                                          4
                                         x  - 1
--------------------------------------------------------------------------------
> ?parfrac
--------------------------------------------------------------------------------
> convert(f,parfrac,x);

                           3           1              x
                       --------- - --------- - 1/2 ------
                       4 (x - 1)   4 (x + 1)        2
                                                   x  + 1
--------------------------------------------------------------------------------
> int(",x);

                                                         2
                 3/4 ln(x - 1) - 1/4 ln(x + 1) - 1/4 ln(x  + 1)
--------------------------------------------------------------------------------
> diff(",x);

                           3           1              x
                       --------- - --------- - 1/2 ------
                       4 (x - 1)   4 (x + 1)        2
                                                   x  + 1
--------------------------------------------------------------------------------
> f:=1/(x^3-1);

                                           1
                                   f := ------
                                         3
                                        x  - 1
--------------------------------------------------------------------------------
> g:=int(f,x);

                               2                 1/2                       1/2
  g := 1/3 ln(x - 1) - 1/6 ln(x  + x + 1) - 1/3 3    arctan(1/3 (2 x + 1) 3   )
--------------------------------------------------------------------------------
> plot(g,x=1..4);
--------------------------------------------------------------------------------
# 

   ** Maple V Graphics **

--------------------------------------------------------------------------------
> limit(g,x,right);
Error, (in limit) invalid arguments

--------------------------------------------------------------------------------
> ?limit
--------------------------------------------------------------------------------
> limit(g,x=1,right);

                                   - infinity
--------------------------------------------------------------------------------
> limit(g,x=1,left);

                                   - infinity
--------------------------------------------------------------------------------
> g(-2);

                                             2
                 1/3 ln(x - 1)(-2) - 1/6 ln(x  + x + 1)(-2)

                             1/2                       1/2
                      - 1/3 3    arctan(1/3 (2 x + 1) 3   )(-2)
--------------------------------------------------------------------------------
> subs(x=-2,g);

                                              1/2           1/2
                1/3 ln(-3) - 1/6 ln(3) - 1/3 3    arctan(- 3   )
--------------------------------------------------------------------------------
> evalf(");

                           .7877018364 + 1.047197551 I
--------------------------------------------------------------------------------
> ln(-3);

                                     ln(-3)
--------------------------------------------------------------------------------
> evalf(");

                           1.098612289 + 3.141592654 I
--------------------------------------------------------------------------------
> subs(x=2.0,g);

                                           1/2                     1/2
         1/3 ln(1.0) - 1/6 ln(7.00) - 1/3 3    arctan(1.666666667 3   )
--------------------------------------------------------------------------------
> evalf(");

                                  -1.038687215
--------------------------------------------------------------------------------
> limit(g,x=infinity);

                                         1/2
                                  - 1/6 3    Pi
--------------------------------------------------------------------------------
> evalf(");

                                  -.9068996827
--------------------------------------------------------------------------------
> int(f,x=0..2);

                                    2
                                    /
                                   |     1
                                   |  ------ dx
                                   |   3
                                  /   x  - 1
                                  0
--------------------------------------------------------------------------------
> evalf(");
Error, (in evalf/int) unable to handle singularity

--------------------------------------------------------------------------------
> int(f,x=0..0.9);

                                                   1/2
             - 1.520747795 + 1.047197551 I + 1/18 3    Pi - 1/3 I Pi
--------------------------------------------------------------------------------
> evalf(");

                                  -1.218447901
--------------------------------------------------------------------------------
> evalf(Int(f,x=0..0.9));

                                  -1.218447901
--------------------------------------------------------------------------------
> int(f,x=2..infinity);

                     1/2                       1/2             1/2
              - 1/6 3    Pi + 1/6 ln(7) + 1/3 3    arctan(5/3 3   )
--------------------------------------------------------------------------------
> evalf(");

                                   .1317875321
--------------------------------------------------------------------------------
> g:=int(exp(-x^2),x);

                                         1/2
                              g := 1/2 Pi    erf(x)
--------------------------------------------------------------------------------
> diff(g,x);

                                           2
                                    exp(- x )
--------------------------------------------------------------------------------
> subs(x=0,g);

                                      1/2
                                1/2 Pi    erf(0)
--------------------------------------------------------------------------------
> erf(0);

                                        0
--------------------------------------------------------------------------------
> ?erf
--------------------------------------------------------------------------------
> int(exp(-x^2),x=0..infinity);

                                          1/2
                                    1/2 Pi
> erf(infinity);

                                        1
--------------------------------------------------------------------------------
> int((sin(x))^4,x);

                            3
                - 1/4 sin(x)  cos(x) - 3/8 cos(x) sin(x) + 3/8 x
--------------------------------------------------------------------------------
> diff(",x);

                  2       2             4             2             2
      - 3/4 sin(x)  cos(x)  + 1/4 sin(x)  + 3/8 sin(x)  - 3/8 cos(x)  + 3/8
--------------------------------------------------------------------------------
> simplify(");

                                      2             4
                            - 2 cos(x)  + 1 + cos(x)
--------------------------------------------------------------------------------
> simplify("-(sin(x))^4);

                                        0
--------------------------------------------------------------------------------
> int(sin(x)/x,x);

                                      Si(x)
> ?Si
--------------------------------------------------------------------------------
> Si(0);

                                        0
--------------------------------------------------------------------------------
> Si(infinity);

                                     1/2 Pi
--------------------------------------------------------------------------------
> Int(sin(x)/x,x=0..infinity)=Si(infinity);

                           infinity
                              /
                             |      sin(x)
                             |      ------ dx = 1/2 Pi
                             |         x
                            /
                            0
--------------------------------------------------------------------------------
> f:='f':
--------------------------------------------------------------------------------
> L(f)=Int(exp(-s*t)*f(t),t=0..infinity);

                               infinity
                                  /
                                 |
                       L(f) =    |      exp(- s t) f(t) dt
                                 |
                                /
                                0
--------------------------------------------------------------------------------
> int(exp(-s*t),t=0..infinity);

                                         exp(- s t)
                        limit          - ---------- + 1/s
                        t -> infinity-        s
--------------------------------------------------------------------------------
> assume(s>0);
--------------------------------------------------------------------------------
> int(exp(-s*t),t=0..infinity);

                                        1
                                      ----
                                       s~
--------------------------------------------------------------------------------
> about(s);
Originally s, renamed s~:
  is assumed to be: RealRange(Open(0),infinity)


--------------------------------------------------------------------------------
> Int(exp(-s*t)*t^(1/2),t=0..infinity)=int(exp(-s*t)*t^(1/2),t=0..infinity);

                     infinity
                        /                                 1/2
                       |                   1/2          Pi
                       |      exp(- s~ t) t    dt = 1/2 -----
                       |                                  3/2
                      /                                 s~
                      0
--------------------------------------------------------------------------------
> Int(exp(-s*t)*exp(t),t=0..infinity)=int(exp(-s*t)*exp(t),t=0..infinity);

  infinity
     /
    |                                               exp(t) exp(- s~ t)      1
    |      exp(- s~ t) exp(t) dt = limit          - ------------------ + ------
    |                              t -> infinity-         s~ - 1         s~ - 1
   /
   0
--------------------------------------------------------------------------------
> additionally(s>1);
--------------------------------------------------------------------------------
> Int(exp(-s*t)*exp(t),t=0..infinity)=int(exp(-s*t)*exp(t),t=0..infinity);

                     infinity
                        /
                       |                                 1
                       |      exp(- s~ t) exp(t) dt = ------
                       |                              s~ - 1
                      /
                      0
--------------------------------------------------------------------------------
> about(s);
Originally s, renamed s~:
  is assumed to be: RealRange(Open(1),infinity)


--------------------------------------------------------------------------------
> s:='s':
--------------------------------------------------------------------------------
> ?laplace
--------------------------------------------------------------------------------
> laplace(1,t,s);

                                       1/s
--------------------------------------------------------------------------------
> laplace(t^(1/2),t,s);laplace(t*exp(t),t,s);laplace(exp(a*t),t,s);\
laplace(sin(b*t),t,s);

                                          1/2
                                        Pi
                                    1/2 -----
                                          3/2
                                         s

                                        1
                                    --------
                                           2
                                    (s - 1)

                                        1
                                      -----
                                      s - a

                                        b
                                     -------
                                      2    2
                                     s  + b
--------------------------------------------------------------------------------
> ?invlaplace
--------------------------------------------------------------------------------
> invlaplace(s/(s^2+b^2),s,t);

                                    cos(b t)
--------------------------------------------------------------------------------
> invlaplace(1/(s-1)^3,s,t);invlaplace(1/sqrt(s^2+b^2),s,t);\
invlaplace(exp(-s^2),s,t);

                                       2
                                  1/2 t  exp(t)

                                 BesselJ(0, b t)

                                             2
                           invlaplace(exp(- s ), s, t)
--------------------------------------------------------------------------------