Question

If x 2 +1/x 2 =14 find the value of x+1/x

Answer 1

x^2 + 1/x^2 = 14, x+1/x= ?

 

(x+1/x)^2 = x^2 + 2 + 1/x^2.

 

But, x^2+1/x^2 = 14 and hence, (x + 1/x)^2 = 14 + 2 = 16.

 

Thus, x + 1/x = sqrt (16) = +/- 4.