Math, asked by mrudulmahajan2009, 4 days ago

\huge\tt\red{P}\tt\pink{L}\tt\blue{E}\tt\green{A}\tt\purple{S}\tt\orange{E}
\huge\tt\red{A}\tt\pink{N}\tt\blue{S}\tt\green{W}\tt\purple{E}\tt\orange{R}

\huge\pink \: \mathfrak{Question}
correct answer will be marked as brainlist
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Answers

Answered by Anonymous
5

Given:

{⇥\rm{a +  \frac{1}{a} = 3 }}

To Find:

{⇥\rm{ {a}^{2}  +  \frac{1}{ {a}^{2} } }}

Solution:

{\rm{ {(a +  \frac{1}{a} )}^{2} }} =  {\rm{ {a}^{2}  + 2 \times {\cancel a \times \frac{1}{\cancel{a}} + \frac{1}{ {a}^{2} }  }}}

{\rm{( {a +  \frac{1}{a}) }^{2} }} =  {a}^{2}  +  \frac{1}{{a}^{2} }  + 2 \\ {\rm{( {a +  \frac{1}{a} )}^{2} - 2 }} = {a}^{2}  +  \frac{1}{{a}^{2} } \\ {\rm{ ({3})^{2} - 2 = {a}^{2}  +  \frac{1}{{a}^{2} }}} \\ {\rm{9 - 2 =  {a}^{2}  +  \frac{1}{{a}^{2} }}} \\

{\rm{7 =  {a}^{2}  +  \frac{1}{ {a}^{2} }  }}

Answer is 7.

Formula used:

{\rm{\red{\boxed{(a+b)² = a²+2ab+b²}}}}

Answered by diwanamrmznu
8

EVALUATION ★

GIVEN★

 =  > a +  \frac{1}{a}  = 3 ...(1

find★

 = a {}^{2} +  \frac{1}{a {}^{2} } \\

solution★

  • EQ (1 both side doing squaring

 =  > (a +  \frac{1}{a} ) {}^{2}  = 3 {}^{2}  \\  \\

we know that

 =  > (a + b) {}^{2}  = a {}^{2}  + b {}^{2}  + 2ab \\

so

 =  > a {}^{2} +  \frac{1 {}^{} }{a {}^{2} }  + 2(a)( \frac{1}{a}  ) = 9 \\  \\  =  > a {}^{2}  +  \frac{1}{a {}^{2} } + 2 = 9 \\  \\  =  > a {}^{2}  +  \frac{1}{a {}^{2} }   = 9 - 2 \\  \\  =  > a {}^{2} +  \frac{1}{a {}^{2} }  = 7

===============

answer★:

option (c) is ✅✅

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I hope it helps you

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