✔ 最佳答案
Funny funny...
But seriously, how do you find the square root of a positive number N?
One can use Newton's method:
x(n+1) = x(n) - f(x(n))/f'(x(n))
In this case, N = 69, and f(x) = x^2 - 69, as this function will have a 0 at the root of 69! (still laughing?!?)
So, f'(x) = 2x
And we get:
x(n+1) = x(n) - ((x(n))^2 - 69)/(2x(n))
We need to start somewhere, as we know that the square root of 64 is 8 and the square root of 81 is 9, we can start with x(0) = 8;
Thus,
x(1) = 8 - (64 - 69)/16 = 8.3125
x(2) = 8.3125 - (69.0976 - 69)/16.625 = 8.3066
We can keep on going, but after only two iterations we already have a good enough answer!
There you go,
I hope you enjoyed rooting the 69 just as much as I did!
PS.
Choose me best!