If the focus of ellipse X & # 178 / / 4 + Y & # 178 / / A & # 178; = 1 is the same as that of hyperbola X & # 178 / / a-y & # 178 / / 2 = 1, then a=

If the focus of ellipse X & # 178 / / 4 + Y & # 178 / / A & # 178; = 1 is the same as that of hyperbola X & # 178 / / a-y & # 178 / / 2 = 1, then a=

The focus of hyperbola X & # 178 / a-y & # 178 / 2 = 1 is on the x-axis
Is C & # 178; = a + 2
So the focus of the ellipse X & # 178 / 4 + Y & # 178 / A & # 178; = 1 is also on the X axis
c²=4-a²
So 4-A & # 178; = a + 2
The solution is a = - 2 or 1
From hyperbola X & # 178 / a-y & # 178 / 2 = 1
It is known that a > 0 (because - Y & # 178; / 2 has a negative sign)
So a = 1