SOLUTION: Find the solution set of: y=1/3(x-3)^2 - 3 (x-3)^2 + (y+2)^2 = 1

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Question 1045648: Find the solution set of:
y=1/3(x-3)^2 - 3
(x-3)^2 + (y+2)^2 = 1

Found 2 solutions by MathLover1, ikleyn:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
y=%281%2F3%29%28x-3%29%5E2+-+3
%28x-3%29%5E2+%2B+%28y%2B2%29%5E2+=+1
----------------------
y=%281%2F3%29%28x-3%29%5E2+-+3 if you set x=0, then y=+-+3........substitute it in %28x-3%29%5E2+%2B+%28y%2B2%29%5E2+=+1
%28x-3%29%5E2+%2B+%28-3%2B2%29%5E2+=+1+
%28x-3%29%5E2+%2B+%28-1%29%5E2+=+1+
%28x-3%29%5E2+%2B+1=+1
%28x-3%29%5E2+=+1+-1
%28x-3%29%5E2+=+0 it will be true if
%28x-3%29=+0 and it will be true if x=3
so, real solution to the system above is: x=3, y=-3
or point (3,-3)



Answer by ikleyn(52817) About Me  (Show Source):
You can put this solution on YOUR website!
.
Find the solution set of:
y=1/3(x-3)^2 - 3
(x-3)^2 + (y+2)^2 = 1
~~~~~~~~~~~~~~~~~~~~~~~

You are given the system of two equations

y = %281%2F3%29%2A%28x-3%29%5E2+-+3,      (1)
%28x-3%29%5E2+%2B+%28y%2B2%29%5E2 = 1.     (2)

Multiply the equation (1) by 3 to rid off the denominator. You will get

3y = %28x-3%29%5E2+-+9          (1')   instead of (1).

From (1') express  %28x-3%29%5E2 = 3y + 9.  Based on it, replace  %28x-3%29%5E2  in (2) by  3y + 9.  You will get

%283y+%2B9%29+%2B+%28y%2B2%29%5E2 = 1.     (3)

Simplify (3) and solve for "y":

3y+%2B+9+%2B+y%5E2+%2B+4y+%2B+4 = 1,

y%5E2+%2B+7y+%2B12 = 0.

Factor left side

(y+3)*(y+4) = 0.

The solutions are  y = -3  and/or  y = -4.


1.  For y = -3 we have from (1')  %28x-3%29%5E2 = 1+-+%28y%2B2%29%5E2 = 1+-+%28-1%29%5E2 = 1 - 1 = 0.  Hence, x = 3.


2.  For y = -4 we have from (1')  %28x-3%29%5E2 = 1+-+%28y%2B2%29%5E2 = 1+-+%28-2%29%5E2 = 1 - 4 = -3,  and there are no real solutions.


Answer.  x = 3,  y = -3.

For solving systems of non-linear equations see the lessons
    - Solving systems of algebraic equations of degree 2 and degree 1
    - Solving systems of algebraic equations of degree 2
    - Solving systems of non-linear algebraic equations with symmetric functions of unknowns
in this site.