Найти f'(0)
f(x)=4x+1/cosx a=π/4

f(x)=4x+1/cosxf`(x)=(4cosx+(4x+1)sinx)/(cos^2x)f`(0)=(4cos0+(4*0+1)sin0)/(cos^2(0))=(4*1+1*0)/1=(4+1)/1=5/1=1