# Calculate integral

1. Feb 14, 2009

### cataldo

I have some problem with following integral. In attachment a pdf with integral..
I have done a integration by sobstitution but i have not a result ....
best regards

#### Attached Files:

• ###### integral.pdf
File size:
41.4 KB
Views:
125
2. Feb 14, 2009

### tiny-tim

why couldn't you type that out?

try substituting so that sin becomes cos of something else.

3. Feb 15, 2009

### cataldo

Ok...
I have done this question because the calculate on site "wolfram mathematica online integrator" only indefinite integral is very complicated and i don't understand as i can obtain this....
Cataldo...

#### Attached Files:

• ###### Wolfram Mathematica Online Integrator.pdf
File size:
37.1 KB
Views:
263
4. Feb 15, 2009

### mathman

By a little manipulation you can transform it into an integral from 0 to 1 of the following:

2[(1+x)1/2 + [(1-x)1/2]/(1-x2). Essentially this was done by collapsing the integral into 0 to pi/2 and then letting x=sin.

See if you can go further.

5. Feb 16, 2009

### cataldo

Ok...Tanks mathman
Is exactly x=sin and integral from 0 to 1.. but i obtain [(1+x)^(1/2)]/(1-x^2)... Does it correct?

6. Feb 16, 2009

### tiny-tim

how about sinx = cos(π/2 - x)?

7. Feb 16, 2009

### mathman

The sin is positive from 0 to pi and negative from pi to 2pi. I first collapsed the second interval into the first, so I had two terms: 1+sin and 1-sin. Next collapsing to 0 to pi/2 with a factor of 2. Finally let x=sin.

8. Feb 17, 2009