函數(shù)f(x)=sinx+cosx在點(diǎn)(0,f(0))處的切線方程為( )
A.x-y+1=0
B.x-y-1=0
C.x+y-1=0
D.x+y+1=0
【答案】分析:先求出f′(x),欲求出切線方程,只須求出其斜率即可,故先利用導(dǎo)數(shù)求出在x=0處的導(dǎo)函數(shù)值,再結(jié)合導(dǎo)數(shù)的幾何意義即可求出切線的斜率.從而問(wèn)題解決.
解答:解:∵f(x)=sinx+cosx
∴f′(x)=cosx-sinx
∴f'(0)=1,所以函數(shù)f(x)在點(diǎn)(0,f(0))處的切線斜率為1;
又f(0)=1,
∴函數(shù)f(x)=sinx+cosx在點(diǎn)(0,f(0))處的切線方程為:
y-1=x-0.即x-y+1=0.
故選A.
點(diǎn)評(píng):本小題主要考查學(xué)生會(huì)利用導(dǎo)數(shù)求曲線上過(guò)某點(diǎn)切線方程的斜率,考查直線的斜率、導(dǎo)數(shù)的幾何意義等基礎(chǔ)知識(shí),考查運(yùn)算求解能力.屬于基礎(chǔ)題.