这个题目吧,很把f(t-x)中的x分离出来
令t-x=y
dt=dy
t=0,y=-x
t=x,y=0
g(x)=∫[-x,0] (x+y)^2f(y)dy
=x^2∫[-x,0] f(y)dy+2x∫[-x,0] yf(y)dy+∫[-x,0] y^2f(y)dy
g'(x)=2x∫[-x,0] f(y)dy-x^2f(x)+2∫[-x,0] yf(y)dy-2x^2f(x)-x^2f(x)
=2x∫[-x,0] f(y)dy-4x^2f(x)+2∫[-x,0] yf(y)dy
这个题目吧,很把f(t-x)中的x分离出来
令t-x=y
dt=dy
t=0,y=-x
t=x,y=0
g(x)=∫[-x,0] (x+y)^2f(y)dy
=x^2∫[-x,0] f(y)dy+2x∫[-x,0] yf(y)dy+∫[-x,0] y^2f(y)dy
g'(x)=2x∫[-x,0] f(y)dy-x^2f(x)+2∫[-x,0] yf(y)dy-2x^2f(x)-x^2f(x)
=2x∫[-x,0] f(y)dy-4x^2f(x)+2∫[-x,0] yf(y)dy