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∫上限X下限0)f(t)dt=cosx^2,则∫上限1下限0)Xf(x^2)d(x)=

题目详情
∫上限X下限0)f(t)dt=cosx^2,则∫上限1下限0)Xf(x^2 )d(x)=
▼优质解答
答案和解析
∫(0→x) ƒ(t) dt = cos(x²),两边都对x求导
ƒ(x) = - 2xsin(x²)
ƒ(x²) = - 2x²sin(x⁴)
∫(0→1) xƒ(x²) dx
= ∫(0→1) x[- 2x²sin(x⁴)] dx
= (- 2)(1/4)∫(0→1) sin(x⁴) d(x⁴)
= (- 1/2)[- cos(x⁴)]:(0→1)
= (1/2)[cos(1) - cos(0)]
= (1/2)cos(1) - 1/2