Question

If f'(x) = cos(3^x), then the smallest value of x for which f has a relative maximum is:

A 0.411
B 1.042
C 1.411
D 1.673

Answer 1

A 0.411

Explanation:

A graph of f'(x) is negative-going at its first zero-crossing of about x=0.411. Thus, this point where the derivative is zero corresponds to a local maximum.

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There are no zero crossings for negative values of x. The curve asymptotically approaches y=1.