# Help with a Trig Identity Problem

• Jun 30th 2007, 09:18 AM
andy11
Help with a Trig Identity Problem
If we establish an identity, sinAcscA - sin2A could equal which of the following quantities?

1
cos^(2) x A
sin^(2) x A – 1
tan^(2) x A

thanks
• Jun 30th 2007, 09:22 AM
topsquark
Quote:

Originally Posted by andy11
If we establish an identity, sinAcscA - sin2A could equal which of the following quantities?

1
cos2A
sin2A – 1
tan2A

thanks

$sin(A)csc(A) - sin^2(A)$<-- I had to be a bit of an oracle here!

$= \frac{sin(A)}{sin(A)} - sin^2(A)$

$= 1 - sin^2(A) = cos^2(A)$

-Dan