Calculus 2: Trigonometric Substitution, using Z = tan(x/2)

kiz
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Homework Statement



2e2jsc8.jpg

Homework Equations



25rlguf.jpg

The Attempt at a Solution



After substituting:

2cf7axc.jpg

Using
14wzxiw.jpg

2yo47qx.jpg

I'm stuck here:
dzlsp.jpg

I can't seem to find anything online about this substitution. Any help would be appreciated. thanks.
 
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kiz said:

Homework Statement



2e2jsc8.jpg

Homework Equations



25rlguf.jpg

The Attempt at a Solution



After substituting:

2cf7axc.jpg

Using
14wzxiw.jpg

2yo47qx.jpg

I'm stuck here:
dzlsp.jpg

I can't seem to find anything online about this substitution. Any help would be appreciated. thanks.

I am so glad I have no need to remember any of this. my computer does all the calculations for me :)
 
http://en.wikipedia.org/wiki/Tangent_half-angle_formula You seem to have turned a '2' into a 'z' in you dx derivation. And you would have to change the limits to 'z' limits instead of 'x' limits if you are going to stick with the variable z. Otherwise just find the indefinite integral in terms of z and change the function back to x.
 
Dick said:
http://en.wikipedia.org/wiki/Tangent_half-angle_formula You seem to have turned a '2' into a 'z' in you dx derivation. And you would have to change the limits to 'z' limits instead of 'x' limits if you are going to stick with the variable z. Otherwise just find the indefinite integral in terms of z and change the function back to x.

Okay, thanks for the help, I'm looking at the solution and it has 1 and \sqrt{3} for the bounds, but I do not get that when insert \frac{\pi}{3} and \frac{\pi}{2}.

EDIT:

I got it, guess I am blind. Thanks again.
 
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