求f(x)的反函數(shù)在a=4時(shí)的函數(shù)值,其實(shí)就是求原函數(shù)在y=4時(shí)的自變量x的值,即求2x³＋3x²＋7x＋4=4時(shí)的x的值即可.2x³＋3x²＋7x=0,x(2x²＋3x＋7)=0,得x=0,即：函數(shù)f(x)的反函數(shù),在a=4時(shí)的函數(shù)值是0.謝謝您，您說(shuō)的對(duì)~~不過(guò)我的問(wèn)題問(wèn)錯(cuò)了~~其實(shí)是求該反函數(shù)在a=4點(diǎn)的導(dǎo)數(shù)~~我已經(jīng)會(huì)算了，該反函數(shù)在a=4點(diǎn)的導(dǎo)數(shù)是1/7， 您說(shuō)對(duì)嗎？^^謝謝沒(méi)事。