From Equation 2, you have gotten two cases, OR .

Case 1: .

Substitute into Equation 1 to give

.

But since for all , that means we can only accept even values of , and therefore, that restricts to be .

When that is the case, .

So the first solution is .

Case 2: .

Substitute into Equation 1 to give

according to Mathematica.

So the second solution is .