导数题,导数题,
导数题,
对f(x)求导,f'(x)=-f'(π/4)sinx+cosx取x=π/4,f'(π/4)=-f'(π/4)√2/2+√2/2f'(π/4)=√2-1,f(π/4)=(√2-1)√2/2+√2/2=1