1.1-sin x+1-cos x=sin x + cos x-1

cos x sin x sin x cos x

2.sec^2x - tan^2 x + tan x= sin x + cos x

sec x

3.sin^3 x - sin x + cos x= cot x - cos^2 x

sin x

4.1 + cot A + sec A_ tan A = sin A + cos A

csc A

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- September 4th 2008, 02:07 AMjohn edgarPlease help me with my proving identities
1.

__1-sin x__+__1-cos x__=__sin x + cos x-1__

cos x sin x sin x cos x

2.__sec^2x - tan^2 x + tan x__= sin x + cos x

sec x

3.__sin^3 x - sin x + cos x__= cot x - cos^2 x

sin x

4.__1 + cot A + sec A___ tan A = sin A + cos A

csc A - September 4th 2008, 03:22 AMtopsquark
Hint: Multiply both sides of the equation by sin(x) cos(x) and then try it.

Convert everything to sines and cosines:

Now add the fractions.

What's ? Hint: It's a familiar identity that has been slightly rewritten.

Convert everything to sines and cosines and simplify:

-Dan