• Aug 6th 2009, 07:25 PM
dannyp32
i need help with these problems
i really dont understand how to do them
1.
[2sin (x)]/[1-cos^2(x)]

• Aug 6th 2009, 08:06 PM
artvandalay11
Quote:

Originally Posted by dannyp32
i need help with these problems
i really dont understand how to do them
1.
[2sin (x)]/[1-cos^2(x)]

$sin^2(x)+cos^2(x)=1$ is a well known identity (one that must be memorized)
So subtract $cos^2(x)$ from both sides to get $sin^2(x)=1-cos^2(x)$ so....
$\frac{2sin(x)}{1-cos^2(x)}=\frac{2sin(x)}{sin^2(x)}=\frac{2}{sin(x) }=2\csc(x)$