Solve the following equation x2 y2 8 x2 y 2Solutionx2 y
Solve the following equation
x^2 + y^2 = 8
x^2 - y = 2
Solution
x^2 + y^2 = 8 ---(1)
x^2 - y = 2 ----(2)
y = x^2 - 2
substitute in equation 1:
x^2 + (x^2 -2)^2 = 8
x^2 + x^4 +4 -4x^2 =8
x^4 - 3x^2 -4 =0
x^4 -4x^2 +x^2 -4 =0
x^2(x^2 -4) + 1( x^2 -4) =0
(x^2 +1)(x^2 -4) =0
x= i, -i ; x = -2 , 2
find y : x^2 -y = 2
y = x^2 -2 = 1 -2 = -1
y = 4 -2 = 2
Solution : (x , y) = ( -i, -1) ( i, -1) ( -2 , 2) and ( 2 , 2)
