f(x)=3x+cos2x+sin2x
f'(x)=3-(sin2x)*(2x)'+(cos2x)*(2x)'
=3-2sin2x+2cos2x
a=f'(π/4)=3-2sinπ/2+2cosπ/2=3-2=1
(a,b)在g(x)=x³上,
则b=g(1)=1
即切线为(1,1)
g'(x)=3x²
切线斜率k=g'(1)=3
切线方程为y-1=3(x-1)
即3x-y-2=0
f(x)=3x+cos2x+sin2x
f'(x)=3-(sin2x)*(2x)'+(cos2x)*(2x)'
=3-2sin2x+2cos2x
a=f'(π/4)=3-2sinπ/2+2cosπ/2=3-2=1
(a,b)在g(x)=x³上,
则b=g(1)=1
即切线为(1,1)
g'(x)=3x²
切线斜率k=g'(1)=3
切线方程为y-1=3(x-1)
即3x-y-2=0