Thread: Evaluate the definite integral. Calculous

need help. I know i got the wrong answer, because i checked in the back of the book, but i have no idea where i messed up. help please

sinx/((1+cosx)^2)dx from the intervals 0 to pie/3

It's hard to know where you messed up without seeing your work, but I would try the substitution:

and the integral becomes:



Can you proceed from here?

yes thank you very much!!! I messed up on the anti derivative of cosx. I forgot to add the negative. Thank you.

Isn't cos(pi/3) = 1/2? Where did you get the 3/2?

you have to add the 1. u= 1 +cosx.

the 3/2? not the 2..

ok so to get the 2 you need to plug the 0 to the equation 1+cosx and that gives you 2. to get the 3/2 you plug in pi/3 to the same formula and that gives you 3/2. the reason that the 2 and the 3/2 switch is because there is a negative in the front and that is a rule.

Sorry forgot about the 1 lol

What did you get for your answer?

i got 1/6

You dont have to change the U values and flip the b, a. You could just evaluate the integrand and plug in your original values.

Yes, I just like for the limits of integration to be in ascending order.

Yeah I see how it works out. And also I figured out how it works out on the other problem