answersLogoWhite

0


Best Answer

There is no simple analytical formula. One possible way to estimate the square root of a number is by iteration. This entails making a guess at the answer and then improving on it. Repeating the procedure should lead to a better estimate at each stage. One such is the Newton-Raphson method.
If you want to find the square root of 2, define f(x) = x^2 – 2. Then finding the square root of 2 is equivalent to solving f(x) = 0.

Let f’(x) = 2x. This is the derivative of f(x) but you do not need to know that to use the N-R method.

Start with x0 as the first guess. Then let xn+1 = xn - f(xn)/f’(xn) for n = 0, 1, 2, … Provided you made a reasonable choice for the starting point, the iteration will very quickly converge to the true answer. It works even if your first guess is not so good:
Suppose you start with x0 = 1 (a pretty poor choice since 1^2 is 1, not 2).
Even so, x3 = 1.4142156863, which is less than 0.0002% from the true value. Finally, remember that the negative value is also a square root.

User Avatar

Wiki User

9y ago
This answer is:
User Avatar
More answers
User Avatar

Wiki User

9y ago

There is no analytical formula to enable you to calculate it. One way to estimate the square root of a number is by iteration. This entails making a guess at the answer and then improving on it. Repeating the procedure should lead to a better estimate at each stage. One such is the Newton-Raphson method.

If you want to find the square root of 2, define f(x) = x^2 – 2. Then finding the square root of 2 is equivalent to solving f(x) = 0.

Let f’(x) = 2x. This is the derivative of f(x) but you do not need to know that to use the N-R method.

Start with x0 as the first guess. Then let xn+1 = xn - f(xn)/f’(xn) for n = 0, 1, 2, … Provided you made a reasonable choice for the starting point, the iteration will very quickly converge to the true answer. It works even if your first guess is not so good:
Suppose you start with x0 = 1 (a pretty poor choice since 1^2 is 1, not 2).
Even so, x3 = 1.4142156863, which is less than 0.0002% from the true value. Finally, remember that the negative value is also a square root.

This answer is:
User Avatar

Add your answer:

Earn +20 pts
Q: A formula to work out the square root of 2?
Write your answer...
Submit
Still have questions?
magnify glass
imp
Related questions

What is the formula for the 2 point form?

The formula is: Square root of (X2 - X1)2+ (Y2 -Y1)2


How do you find the square root of a quarter?

To find the square root of a quarter, you can use the formula for square roots. The square root of a number x is a number that, when multiplied by itself, gives x. In this case, the square root of 1/4 (a quarter) is 1/2, because (1/2) * (1/2) = 1/4. Therefore, the square root of a quarter is 1/2.


What is the formula of distance?

It is the same as the distance formula. DISTANCE FORMULA: d=square root of (x2-x1)^2+(y2-y1)^2


What is the square root of the square root of 2?

The square root of the square root of 2


How do you work out 7 - square root of 5 squared?

2


If A(-2-4) and B(-8-4) what is the length of AB?

AB can be found by using the distance formula, which is the square root of (x2-x1)^2 + (y2-y1)^2. In this case, AB= the square root of (-2-(-8))^2 + (-4-(-4))^2 which AB= the square root of 64 + 0 which AB=8.


What is 2 times the square root of 2 squared?

4 the way you work this is: 2*(sqrt)2^2 the square root cancels out the exponent, so your left with 2*2


What is the formula to find out the square root of 20?

The square root of 20 is an irrational number that can be expressed as 2 times square root of 5


What is the derivative of square root of x-5?

Use the formula for the derivative of a power. The square root of (x-5) is the same as (x-5)1/2.


What is 4 square root of 2 minus 2 square root of 2?

2 square root 2


Find dydxsquare root x?

Write square root of x as x1/2. Then use the formula for the derivative of a power.


Formula for finding the length of a line?

It is the square root of: (x1-x2)2+(y1-y2)2