SOLUTION: verify that each of the following is an identity: 1) cos x/ 1-sin^2x= sec x 2) sec x/sin x - sin x/cos x = cot x 3) 1+tan^2�/ cos ^2� = sec^4 � I really need ur help :) thank

Question 204698: verify that each of the following is an identity:
1) cos x/ 1-sin^2x= sec x
2) sec x/sin x - sin x/cos x = cot x
3) 1+tan^2�/ cos ^2� = sec^4 �
I really need ur help :) thank u so much
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
verify that each of the following is an identity:
1) cos x/ 1-sin^2x= sec x
cosx/(cos^2x) = secx
1/cosx = secx
secx = secx
--------------------------------
2) sec x/sin x - sin x/cos x = cot x
Multiply thru by (sinx)(cosx) to get:
(secx)(cosx) - (sinx)(sinx) = (cosx/sinx)(sinx)(cosx)
---
1 - sin^2 = cos^2x
cos^2x = cos^2x
--------------------------------
3) 1+tan^2�/ cos ^2� = sec^4 �
sec^2x/cos^2x = sec^4x
1/cos^4x = sec^4x
sec^4x = sec^4x
========================================
Cheers,
Stan H.

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