利用者:SavannahStevenso

Will try integration by parts.

uv - int[v du]

u = sec(x)----------------du = sec(x) tan(x)

dv = tan(x)---------------v = ln[sec(x)]

sec(x) ln[sex(x)] - int[lnsec(x) dx]

= sec(x) ln[sec(x)] - xlnsec(x) - x + C

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Here is my web site - phim cap 3