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If N=(sqrt(sqrt(5)+2)+sqrt(sqrt(5)-2))/(...

If `N=(sqrt(sqrt(5)+2)+sqrt(sqrt(5)-2))/(sqrt(sqrt(5)+1))-sqrt(3-2sqrt(2)` then `sqrtN` equals____

A

1

B

`2sqrt(2)-1`

C

`(sqrt(5))/2`

D

`2/(sqrt(sqrt(5)+1))`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to simplify the expression for \( N \) given by: \[ N = \frac{\sqrt{\sqrt{5}+2} + \sqrt{\sqrt{5}-2}}{\sqrt{\sqrt{5}+1}} - \sqrt{3 - 2\sqrt{2}} \] ### Step 1: Simplify the term \( \sqrt{3 - 2\sqrt{2}} \) We can rewrite \( 3 - 2\sqrt{2} \) as a square: \[ 3 - 2\sqrt{2} = (\sqrt{2} - 1)^2 \] Thus, we have: \[ \sqrt{3 - 2\sqrt{2}} = \sqrt{(\sqrt{2} - 1)^2} = \sqrt{2} - 1 \] ### Step 2: Substitute back into the expression for \( N \) Now substituting this back into \( N \): \[ N = \frac{\sqrt{\sqrt{5}+2} + \sqrt{\sqrt{5}-2}}{\sqrt{\sqrt{5}+1}} - (\sqrt{2} - 1) \] This simplifies to: \[ N = \frac{\sqrt{\sqrt{5}+2} + \sqrt{\sqrt{5}-2}}{\sqrt{\sqrt{5}+1}} - \sqrt{2} + 1 \] ### Step 3: Simplify the numerator \( \sqrt{\sqrt{5}+2} + \sqrt{\sqrt{5}-2} \) Let’s denote: \[ a = \sqrt{\sqrt{5}+2}, \quad b = \sqrt{\sqrt{5}-2} \] Now, we can find \( a^2 + b^2 \) and \( ab \): \[ a^2 = \sqrt{5} + 2, \quad b^2 = \sqrt{5} - 2 \] Adding these gives: \[ a^2 + b^2 = (\sqrt{5} + 2) + (\sqrt{5} - 2) = 2\sqrt{5} \] Now, for \( ab \): \[ ab = \sqrt{(\sqrt{5}+2)(\sqrt{5}-2)} = \sqrt{5 - 4} = 1 \] ### Step 4: Calculate \( a + b \) Using the identity \( (a+b)^2 = a^2 + b^2 + 2ab \): \[ (a+b)^2 = 2\sqrt{5} + 2 = 2(\sqrt{5} + 1) \] Thus, we have: \[ a + b = \sqrt{2(\sqrt{5}+1)} \] ### Step 5: Substitute \( a + b \) back into \( N \) Now substituting \( a + b \) back into \( N \): \[ N = \frac{\sqrt{2(\sqrt{5}+1)}}{\sqrt{\sqrt{5}+1}} - \sqrt{2} + 1 \] This simplifies to: \[ N = \sqrt{2} - \sqrt{2} + 1 = 1 \] ### Step 6: Find \( \sqrt{N} \) Finally, we find: \[ \sqrt{N} = \sqrt{1} = 1 \] Thus, the value of \( \sqrt{N} \) is: \[ \boxed{1} \]
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