已知函數(shù)f(x)的導函數(shù)f'(x)=5+余弦x,x屬于(-1,1)且f(0)=0,若f(1-x)+f(1-x^2)
已知函數(shù)f(x)的導函數(shù)f'(x)=5+余弦x,x屬于(-1,1)且f(0)=0,若f(1-x)+f(1-x^2)
數(shù)學人氣:895 ℃時間:2020-05-11 04:23:53
優(yōu)質(zhì)解答
f'(x)=5+cosx>0,所以f(x)單調(diào)遞增
上式兩端積分得f(x)=5x+sinx+C
又f(0)=0 所以C=0,f(x)=5x+sinx為奇函數(shù)
f(1-x)+f(1-x^2)<0
即f(1-x)<-f(1-x^2)=f(x^2-1)
又f(x)遞增 1-x(x-1)(x+2)>0
x>1或x<-2
再結(jié)合定義域-1<1-x<1,-1<1-x^2<1,
即0所以1