Question

Why does the second part of the problem cos x turns into cos x^2 explain the problem.

Answer 1

Explanation:

It's not cos x^2

`\cos^2x\\eq\cos x^2`

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`\cos x-(\sin x\sin x)/(\cos x)=(\cos x\cos x)/(\cos x)-(\sin x\sin x)/(\cos x)=(\cos^2-\sin^2x)/(\cos x)`

It's the same as

`3-(2)/(3)=(3\cdot3)/(3)-(2)/(3)=(3^2-2)/(3)`