求∫（tanx^2+cotx^2）dx
问题描述：
求∫（tanx^2+cotx^2）dx
答
∫(tan²x+cot²x) dx
= ∫tan²x dx + ∫cot²x dx
= ∫(sec²x-1) dx + ∫(csc²x-1) dx
= tanx - x - cotx - x + C
= tanx - cotx - 2x + C