Question

If `x^4+1/x^4=119, "find"  x^2+1/x^2.`

Answer 1

Here, `x^4+1/x^4=119,`

Let, A = `x^2+1/x^2`

We know that,

`x^4+1/x^4=(x^2+1/x^2)^2-2`

Substitute the value:

119 = a² − 2

a² = 119 + 2

a² = 121

∴ a = `+-sqrt121`

∴ a = ±11