Question

If a= 7-4√3 . find the value of a+1/√a . plzz tell the write solution ..

Answer 1

Sol : Given , a = 7 - 4√3.  -------------- equation 1

So, 1 / a = 1 / ( 7 - 4√3 )

 
By multiplying the numerator and denominator of R.H.S by ( 7 + 4√3 ).

= 1 x ( 7 + 4√3 ) / ( 7 - 4√3 ) ( 7 + 4√3 )

= ( 7 + 4√3 ) / { ( 7 )² - ( 4√3 )² }    [ ( a + b ) ( a - b ) = a² - b² ]

= ( 7 + 4√3 ) / { 49 - 48 ]

= ( 7 + 4√3 )  = 1 / a   ------------ equation 2

By adding equation 1 and equation 2 ,

a + ( 1 / a ) = 7 - 4√3 + 7 + 4√3

a + ( 1 / a ) = 14.

The answer for your question is 14.

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