cos(cotan x)?

Question

a. x(sqrt x^2 + 1) / x^2 + 1
b. x(sqrt x^2 + 1)
c. (sqrt x^2 - 1) / x^2 - 1
d. (sqrt x^2 + 1) / x^2 + 1

Answer 1

hmmm....

if i can decipher the real question...

cot θ = x
you need an expression for cos θ in terms of x.

cot θ = x... then cot^2(θ) + 1 = csc^2(θ) = 1 + x^2
then
cos θ = cot θ * csc θ

thus
cos θ = x * sqrt(1 + x^2)

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Answer 2

What's the question here?
What do you want to do with these expressions?