第1个回答 2012-02-07
(tanx - tan³x)/(1 + 2tan²x + tan^4(x))
= (tanx - tan³x)/(1 + tan²x)²
= (tanx - tan³x)/(sec²x)²
= (tanx - tan³x) * cos^4(x)
= sinx cos³x - sin³x cosx
= sinx cosx (cos²x - sin²x)
= sinx cosx cos2x
= (1/2) sin2x cos2x
= (1/4) sin4x
最大值是1/4,最小值是-1/4
它们的积是-1/16