Find the largest value of x for which
x^2 + y^2 = x + y + 4
has a solution, if x and y are real.
We visualize the equation as a circle on the coordinate plane.
Graph: https://www.desmos.com/calculator/swjzoksjmi
The circle is centered at \(\left(\dfrac12, \dfrac12\right)\) and has a radius \(\dfrac{3\sqrt 2}2\). Therefore, for the largest value of x, we find the maximum possible x-coordinate on the circle, i.e., the x-coordinate of the right-most point.
\(\max x = \dfrac12 + \text{radius of circle} = \dfrac{1 + 3\sqrt 2}2\)
Further explanations are typed in the graph.
We visualize the equation as a circle on the coordinate plane.
Graph: https://www.desmos.com/calculator/swjzoksjmi
The circle is centered at \(\left(\dfrac12, \dfrac12\right)\) and has a radius \(\dfrac{3\sqrt 2}2\). Therefore, for the largest value of x, we find the maximum possible x-coordinate on the circle, i.e., the x-coordinate of the right-most point.
\(\max x = \dfrac12 + \text{radius of circle} = \dfrac{1 + 3\sqrt 2}2\)
Further explanations are typed in the graph.