函数y=xcos2x在点(π/4,0)处的切线方程是

函数y=xcos2x在点(π/4,0)处的切线方程是
函数y=xcos2x在点(π/4,0)处的切线方程是

函数y=xcos2x在点(π/4,0)处的切线方程是
y'=cos2x=2xsinx
y'i=π/4=-(根号2)×π/4
4π（根号2）x+16y+π^2(根号2）=0

Y^=COS2X+X(-SIN2X)2