Suppose that the function y=tanwx is a monotonically decreasing function in (-π/2, π/2), and the range of w is:

A.0〈w≤ 1

B.- 1≤w〈0

C.w≥ 1

D.w≤- 1

Choose B, bring in 1, -2, and it is easy to exclude ACD.

The concrete way is that the composite function should have learned W.

If the external function is monotonically increasing, then the internal function wx must be monotonically decreasing.

Wx guarantee range is (-π/2, π/2).

X belongs to (-π/2, π/2), so W must be-1

Please adopt what you think is good.