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3 votes
Which equation is not an identity?

tan(–t) = –tan t



tan t(csc t + cot t) = sec t + 1



sin tcot t = cos t



cos2t − sin2t = –1

2 Answers

6 votes
Not 100% positive but i believe it is the third choice
User Shubham Chahal
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8.2k points
6 votes
Hey there,

Let t = 0 and you'd get 1 - 0 = -1 which is false

I would go for (D)
User Lucas Ferreira
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7.8k points