Questions on Algebra: Trigonometry answered by real tutors!

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Question 149422: If we establish an identity:
(tan A - cot A/tan A + cot A) would equal what?: If we establish an identity:
(tan A - cot A/tan A + cot A) would equal what?
Answer by jojo14344(832) About Me  (Show Source):
You can put this solution on YOUR website!
Re-writing,
(tanA-cotA)/(tanA+cotA)
By quotient identities:
=((sinA/cosA)-(cosA/sinA))/((sinA/cosA)+(cosA/sinA))
=((sin^2(A)-cos^2(A))/cross((cosA)(sinA)))/((sin^2(A)+cos^2(A))/cross((cosA)(sinA)))
=(sin^2(A)-cos^2(A))/(sin^2(A)+cos^2(A)) = (sin^2(A)-cos^2(A))/1-->A
We have to remember the identity for "double angle formulas":
cos2(mu)=cos^2(mu)-sin^2(mu) --------------> B
*note" (mu)=A
So,
= -cos2A, FINAL ANSWER ----> see the negative (-) sign, bec. the final answer A is opposite the identity B.
Thank you,
Jojo