设x=0,Δx=-0.1所以f(x+Δx)-f(x)≈f'(x)Δx所以f(x+Δx)＝f(x)+f'(x)Δx其中x=0,Δx=-0.1所以f(-0.1)＝e^(-0.1)＝e^0-0.1e^(0)＝0.9
