Hi,

I have two questions I'd like some help with.

Firstly what is dx ?

I tried doing it with trigonometric identities for but it became very nasty pretty fast. Any help would be great.

Also, this has been bugging me all day, and I can't see where I am wrong, though I must be... Why is the integral of yet

Because yet is not the same as

What am I doing wrong?

Thanks.