# Math Help - calculas problem

1. ## calculas problem

Find .

Any help would be appreciated cheers x

2. Originally Posted by Haris
Find .

Any help would be appreciated cheers x
Substitute $u = 4 + \cos (y)$.

3. Originally Posted by Haris
Find .

Any help would be appreciated cheers x
Let $z=4+\cos y\implies \,dz=-\sin y\,dy$

Thus, the integral transforms into $-7\int\frac{\,dz}{z}$

Can you take it from here?

4. I got -7ln(4+cos(y))+C but its wrong i think?

5. Originally Posted by Haris
I got -7ln(4+cos(y))+C but its wrong i think?
Don't be so helpless. Try to differentiate it and see whether you get the integrand ....