Question

if x=root 5+2 then prove that x square +1/x square=18

Answer 1

x = √5+2
1/x= 1/√5+2
on rationalize
multiply √5-2 on nominator or denominator
1/x=√5-2/5-4⇒√5 - 2
according to question
x²+(1/x)²
x=√5 +2
x²=5+4+10√5
1/x=√5-2
(1/x)²=5+4-10√5
According to question
5+4+10√5+5+4-10√5⇒18
hence proved....................................................

Answer 2

Answer:

if x= 5 + root 2 than find the value of x square + 1/x square