To determine the intercepting point of the curves (not
lines), we'll have to solve the system of equations of the
curves.
We'll write the
system:
2y^2 =3x^2+5
3x^2 -
2y^2 = -5 (1)
xy = 12 (2)
We
recognize an a homogenous system and the solving strategy is to eliminate the numbers
alone.
For this reason, we'll multiply the 1st equation by
12 and the 2nd equation by 5:
36x^2 - 24y^2 = -60
(3)
5xy = 60 (4)
We'll add (3)
and (4):
36x^2 + 5xy - 24y^2 =
0
We'll divide by x^2:
36 +
5y/x - 24y^2/x^2 = 0
We'll substitute y/x =
t:
-24t^2 + 5t + 36 = 0
24t^2
- 5t - 36 = 0
We'll apply quadratic
formula:
t1 =
[5+sqrt(25+3456)]/48
t1 =
(5+59)/48
t1 = 4/3
t2 =
(5-59)/48
t2 = -9/8
We'll put
y/x = 4/3
y = 4x/3
We'll
substitute y in the 2nd equation:
x*(4x/3) =
12
4x^2 = 4*9
x^2 =
9
x1 = 3 and x2 = -3
y1 = 4
and y2 = -4
y/x = -9/8
y =
-9x/8
-9x^2 = 8*12
-3x^2 =
32
x^2 = -32/3
This equation
has no real solutions.
The intercepting
points of the curves are represented by the following real solutions of the system, that
are: {(3 ; 4) ; (-3 ; -4)}.
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