=∫dx/(2cos^2(x/2)+1)=∫sec^(x/2)dx/(2+sec^2(x/2))怎么出来的?=∫dx/(2cos^2(x/2)+1)=∫sec^(x/2)dx/(2+sec^2(x/2))求详细流程,我知识点.

∫(2/cos^2x)dx= ∫(1-cos^(2)2x)dx ∫1/(1+cos^2(x)) dx ∫cos(x+2)dx=多少 ∫(1+sinx) / cos^2 x dx 不定积分cos(x^1/2)dx=? cos(x^2)dx ∫cos(2x+1)^5dx=? 微积分1/cos^2(x)dx=?微积分1/cos^2(x)dx＝? ∫x*(cos^2x)dx ∫x／[(cos^2)x]dx ∫sin(x) cos^2(x)dx ∫(1+sin^2x)/(cos^2x)dx ∫sin^3(x)cos^2(x)dx= ∫[1/(sin^2(x)cos^4(x)]dx 求解∫1/(cos^4(x)sin^2(x))dx ∫ x cos(x^2 + 1)dx 请问怎决解? ∫cos^2(x/2)dx