Question

If x+1x=√5, find the value of x2+1x2?

Answer 1

x2−(1x)2=(x+1x)(x−1x)x2−(1x)2

=(x+1x)(x−1x)

We know that 

(a+b)2=(a−b)2+4ab(a+b)2

=(a−b)2+4ab

Hence, (x+1x)2

=(x−1x)2+4⋅x⋅1x

=25+4=29

Answer 2

Answer:

Step-by-step explanation: