Question

Найти производную а)f (x)=lnx×cosx
b)f (x)=5×e-x
помогите

Answer 1

a)
f ' (x) = ( lnx* cosx) ' = (lnx)' cosx  +(cosx)' lnx = cosx/x - sinx*lnx 

b)
f ' (x) = 5*(e^(-x)) ' = 5*e^(-x) *(-x)' = - 5*e^(-x)