1
y=sinxf(π)=f(2π)=0
y'=cosx
cos§=0 (π<§<2π)
§=3π/2
2
f(x)=arctanx
f'(x)=1/(1+x^2)
f(1)-f(0)=f'(§)(1-0)
π/4-0=1/(1+§^2)
§=根号(4/π-1)