Question

2^x=x^2的那个负数解怎么表示

Answer 1

2^x = x^2 求

f(x) = 2^x - x^2

然后 f(x) = 0

x[i+1] = x[i] - f(x[i])/f'(x[i])

f'(x) = 2^x * ln(2) - 2x

x[i+1] = x[i] - (2^x[i]-x^2)/(2^x[i]*ln(2)-2x)

→ x = -0.766664696

验算:

2^-0.766664696 = 0.587774756

(-0.766664696)^2 = 0.587774756