Can a Limit Converging to the Square Root of x be Proven from Given Statements?

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Homework Statement


I have given the statements: ##a_{n}^2 \ge x## , ##a_{n+1} \le a_{n}## , ##x > 0## and ##\inf a_{n} > 0 ##. How to prove the following: ##\lim_{n \to \infty}a_{n}=\sqrt{x}##

Homework Equations


##a_{n}^2 \ge x## , ##a_{n+1} \le a_{n}## , ##x > 0## and ##\inf a_{n} > 0 ##
##\lim_{n \to \infty}a_{n}=\sqrt{x}##

The Attempt at a Solution


I have come so far: $$a_{n}\ge a_{n+1} \ge \sqrt{x}$$ How shall I continue?
 
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3102 said:

Homework Statement


I have given the statements: ##a_{n}^2 \ge x## , ##a_{n+1} \le a_{n}## , ##x > 0## and ##\inf a_{n} > 0 ##. How to prove the following: ##\lim_{n \to \infty}a_{n}=\sqrt{x}##

Homework Equations


##a_{n}^2 \ge x## , ##a_{n+1} \le a_{n}## , ##x > 0## and ##\inf a_{n} > 0 ##
##\lim_{n \to \infty}a_{n}=\sqrt{x}##

The Attempt at a Solution


I have come so far: $$a_{n}\ge a_{n+1} \ge \sqrt{x}$$ How shall I continue?

Are you sure that's the problem? There's not enough information there to show that the limit is ##\sqrt{x}##
 
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You can't prove this, it is not true!

For example, a decreasing sequence that converges to \sqrt{x+ 1} will satisfy all the hypotheses of your "theorem".
 
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There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...

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