SOLUTION: If f(cosx) = cotx and 0 < x < 0.2 find a formula for f(2x)

In the interval  0 < x < 0.2, the cotangent function, expressed in terms of cos(x), is

    cot(x) =  = .


It means that the analytical expression for f(x) in terms of x is

    f(x) = .


Then  f(2x) =  = .


ANSWER.  If f(cosx) = cot(x) and 0 < x < 0.2, then f(2x) = .