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If a+1a=12 a+ \frac{1}{a}=12a+a1​=12​, then find the value of a2+1a2 a^{2}+ \frac{1}{a^{2}}a2+a21​​.
Question

If a+1a=12 a+ \frac{1}{a}=12​, then find the value of a2+1a2 a^{2}+ \frac{1}{a^{2}}​.

A.

144

B.

146

C.

142

D.

140

Correct option is C

Given:a+1a=12a+ \frac{1}{a}=12​​

Formula Used:

(a+b)2=a2+b2+2ab(a+b)^{2} = a^{2}+b^{2} + 2ab​​

Solution:

a+1a=12a+ \frac{1}{a}=12​​

Squaring both sides:

(a+1a)2=122(a+ \frac{1}{a})^{2}=12^{2}​​

a2+1a2+2(a)(1a)=144a^{2}+ \frac{1}{a^{2}}+2(a)( \frac{1}{a})=144​​

a2+1a2+2=144a^{2}+ \frac{1}{a^{2}}+2 =144​​

a2+1a2=1442=142a^{2}+ \frac{1}{a^{2}} =144-2 = 142​​

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