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If the average of x and 1/x(x ne 0) is M...

If the average of x and `1/x(x ne 0)` is M, then the average of `x^2` and `1/x^(2)` is:

A

a) `1- M^(2)`

B

b) `1- 2M`

C

c) `2M^(2)-1`

D

d) `2M^(2) + 1`

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AI Generated Solution

The correct Answer is:
To solve the problem step by step, we need to find the average of \( x^2 \) and \( \frac{1}{x^2} \) given that the average of \( x \) and \( \frac{1}{x} \) is \( M \). ### Step 1: Write the expression for the average of \( x \) and \( \frac{1}{x} \) The average of \( x \) and \( \frac{1}{x} \) is given by: \[ \text{Average} = \frac{x + \frac{1}{x}}{2} = M \] ### Step 2: Rearrange the equation to find \( x + \frac{1}{x} \) From the average expression, we can rearrange it to find: \[ x + \frac{1}{x} = 2M \] ### Step 3: Square both sides to find \( x^2 + \frac{1}{x^2} \) Now, we will square both sides of the equation: \[ \left(x + \frac{1}{x}\right)^2 = (2M)^2 \] This expands to: \[ x^2 + 2 + \frac{1}{x^2} = 4M^2 \] ### Step 4: Isolate \( x^2 + \frac{1}{x^2} \) From the squared equation, we can isolate \( x^2 + \frac{1}{x^2} \): \[ x^2 + \frac{1}{x^2} = 4M^2 - 2 \] ### Step 5: Find the average of \( x^2 \) and \( \frac{1}{x^2} \) Now, we need to find the average of \( x^2 \) and \( \frac{1}{x^2} \): \[ \text{Average} = \frac{x^2 + \frac{1}{x^2}}{2} \] Substituting the value we found in Step 4: \[ \text{Average} = \frac{4M^2 - 2}{2} \] This simplifies to: \[ \text{Average} = 2M^2 - 1 \] ### Final Answer Thus, the average of \( x^2 \) and \( \frac{1}{x^2} \) is: \[ \boxed{2M^2 - 1} \]
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