例。设f(x)eC[-a,a](1)若f(-x)= f(x), 则[ f(x)dx=2{~f(x)dx(2)若f(-x)=-f(x), 则{ f(x)dx= 0证：f(x)dx= [f(x)dx + Jaf(x)dxJf(-t)dt + J°f(x)dx['l f(-x)+ f(x)]dx2J°f(x)dx,f(-x)= f(x)时f(-x)=-f(x)时福HIGH EDUCATION PRESS机动目录上页下页返回结束
例. 证: (1) 若 − = a a a f x x f x x 0 则 ( ) d 2 ( ) d = − f x x a a ( ) d (2) 若 ( ) d = 0 − a a 则 f x x f x x a ( )d 0 − f x x a ( ) d 0 + f t t a ( ) d 0 = − f x x a ( ) d 0 + f x f x x a [ ( ) ( )]d 0 = − + f (−x) = f (x)时 f (−x) = − f (x)时 机动 目录 上页 下页 返回 结束 =
2x2 + x cos x计算dx1+V1-x2HIGHEDUCATIONPRESS