f(2x)=(2X)的平方+3X-1
F(t)=t^2+1.5*t-1
F'(t)=2*t+1.5
f(2x)=2(X的平方)+3X-1
F(t)=0.5*t^2+1.5*t-1
F'(t)=t+1.5