∫sec(x) = ln(sec(x) + tan(x))
∫sec³(x)dx
= ∫sec(x)sec²(x)dx
∫udv = uv - ∫vdu
u = sec(x)
du = sec(x)tan(x)dx
dv = sec²(x)dx
v = tan(x)
∫sec³(x)dx
= ∫sec(x)sec²(x)dx
= sec(x)tan(x) - ∫tan(x)sec(x)tan(x)dx
= sec(x)tan(x) - ∫tan²(x)sec(x)dx
= sec(x)tan(x) - ∫((sec²(x) - 1)sec(x))dx
= sec(x)tan(x) - ∫(sec³(x) - sec(x))dx
= sec(x)tan(x) - ∫sec³(x)dx + ∫sec(x)dx
= sec(x)tan(x) + ln(sec(x) + tan(x)) + c1 - ∫sec³(x)dx
2∫sec³(x)dx = sec(x)tan(x) + ln(sec(x) + tan(x)) + c1
∫sec³(x)dx = (1/2)(sec(x)tan(x) + ln(sec(x) + tan(x))) + c
本回答被提问者采纳你是不是看错了。x方加b方上有根号,后面也一样啊,中间是减号,还是定积分啊。
追答。。。。。。。。。。。。。。。。。。