Question

Se Y² = 1 + x², então quanto vale y^4?

Answer 1

Se, Y² = 1 + x²,
y ^ 4 = ( 1 + x² ) . 2

Answer 2

$y^{2} = 1 + x^{2} \\ \\ y^{4} = (1 + x^{2})^{2} \\ \\ y^{4} = 1^{2} + 2*1*x^{2} + x^{4}$

Portanto:

$y^{4} = 1 + 2x^{2} + x^{4}$