Question

Guys, couple tips for simplifying trigonometric functions.

Answer 1

sinx × cscx =1 sin^2x + cos^2x = 1
cosx × secx =1 sec^2x - tan^2x = 1
cotx × tanx = 1 csc^2x - cot^2x = 1

This is basic.

Answer 2

HALF ANGLE IDENTITIES.
\[\sin(\frac{x}{2})=±\sqrt{\frac{1-cosx}{2}}\] \[\cos(\frac{x}{2})=±\sqrt{\frac{1+cosx}{2}}\]
\[\tan(\frac{x}{2})=±\sqrt{\frac{1-cosx}{1+\cos}}=\frac{1-cosx}{sinx}=\frac{sinx}{1+cosx}\]

Answer 3

More help?

Answer 4

it helps to take everything down to sines and cosines

Answer 5

Yep, thanks for appreciating!

Answer 6

Don't forget the double angle ones.

Answer 7

\[\sin(2x)=2sinxcosx\]
\[\cos(2x)=\cos^2x-\sin^2x=2\cos^2x-1=1-2\sin^2x\]
\[\tan(2x)= \frac{2tanx}{1-\tan^2x}\]

Answer 8

Yes, those are really useful.

Answer 9

http://math2.org/math/trig/identities.htm

Just in case....