Question

∫sec^2x/(2+sec^2x)d(x)不定积分

Answer 1

原式=∫d(tanx)/(3+(tanx)^2)

=(1/√3)∫d(tanx/√3)/(1+(tanx/√3)^2)

=(1/√3)arctan(tanx/√3)+C (C是积分常数).