關於解方程式的問題...解方程式?

用正常方法應解不出答案，唯有用數值分析去做。用牛頓法(Newton's method)吧。

設f(r) = e-r - 0.05r

現在要解出f(r) = 0

f'(r) = -e-r - 0.05

根據牛頓法，rn+1 = rn - f(rn)/f'(rn)

估算r0 = 1.5

r1 = r0 - f(r0)/f'(r0) = 2.042342743

r2 = r1 - f(r1)/f'(r1) = 2.195951823

r3 = r2 - f(r2)/f'(r2) = 2.204975101

r4 = r3 - f(r3)/f'(r3) = 2.205003278

所以，至4位有效數字，

r = 2.2050