Question

if (f)x =x2-3root2z-1 then find f(3root2).
plz give me full answer
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Answer 1

Answer:

Given :  x=3+3(2)1/2

To find the value of x2+1/(x2)

 

x2 = (3+3(2)1/2)    { (a+b)2 = a2 + b2 + 2ab)}

    = 32 + (3(2)1/2) + 2 (3)(3 (21/2))

    = 9 + 9(2) + 18 (21/2)  

x2  = 27 + 18 (21/2)......................(1)

 

according to the question  

=> x2+1/(x2)  

=> 27 + 18 (21/2) + 1/ ( 27 + 18 (21/2))    {using eq1}

=> ( (27 + 18 (21/2))2+1 ) / ( 27 + 18 (21/2))

=>( 729 + 648 + 2(27)(18(21/2)) +1) / ( 27 + 18 (21/2))  { applying (a+b)2 = a2+b2+ 2ab}

=>  (1378 + 972 (21/2) ) / ( 27 + 18 (21/2))

rationliasing the equation, we get

=> [(1378 + 972 (21/2) )( 27 - 18 (21/2)) ]/ [ 272-(18 (21/2))2 ]            { using (a+b)(a-b)= a2 -b2}

= [37206 - 34992 + 24804(21/2) ] /81

= [2214 +24804(21/2) ] / 81 Answer

Step-by-step explanation:please make me brainlest