a-maths!!!!!!!

沒有準確值的答案, 可以用牛頓法計算出大概值如下:
考慮 f(x) = 3(sec x + cot x) - 13, 則 f'(x) = 3(sec x tan x - csc2 x)
由 x0 = 1.5 開始計:
x1 = x0 - f(x0)/f'(x0) = 1.4502
x2 = x1 - f(x1)/f'(x1) = 1.3895
x3 = x2 - f(x2)/f'(x2) = 1.3417
x4 = x3 - f(x3)/f'(x3) = 1.3216
x5 = x4 - f(x4)/f'(x4) = 1.3247
x6 = x5 - f(x5)/f'(x5) = 1.3232
x7 = x6 - f(x6)/f'(x6) = 1.3232
即 0.421π
以相同手法, 在 0 ≦ x ≦ 2π 中能找到另一個答案為:
4.9336 = 1.570π