If x2 - 21x + 1= 0
and x > 1, then the value of
x2 + \(\frac{1}{x^2}\) will be:
Answer & explanation
Correct answer: option 2
If x2 - 21x + 1= 0
Divide by x on both sides,
x + \(\frac{1}{x}\) = 21
x2 + \(\frac{1}{x^2}\) = 212 - 2 = 439
If x + \(\frac{1}{x}\) = a
then, x2 + \(\frac{1}{x^2}\) = a2 - 2