计算∫π/40[x/(1+cos2x)]dx.
∫π/40[x/(1+cos2x)]dx=∫π/40 (x/cos2x)]dx=(1/2) ∫π/40xsec2 xdx =(1/2)∫π/40xd(tan x) =(1/2)(xtanx∣π04-∫π/4 0tan xdx) =(1/2)(π/4+ln(cos x)∣π/40xd(tan x) =π/8-(1/4)ln 2
计算∫π/40[x/(1+cos2x)]dx.
∫π/40[x/(1+cos2x)]dx=∫π/40 (x/cos2x)]dx=(1/2) ∫π/40xsec2 xdx =(1/2)∫π/40xd(tan x) =(1/2)(xtanx∣π04-∫π/4 0tan xdx) =(1/2)(π/4+ln(cos x)∣π/40xd(tan x) =π/8-(1/4)ln 2