# Math Help - Largest Possible y Value

1. ## Largest Possible y Value

If y = -x^2 + 3, what is the largest possible value of y?

2. Originally Posted by magentarita
If y = -x^2 + 3, what is the largest possible value of y?
Again... differentiate wrt y, set equal to zero, solve for x, and put x value back into original equation!

$\frac{dy}{dx} = -2x = 0$

3. Originally Posted by magentarita
If y = -x^2 + 3, what is the largest possible value of y?
Hello Magentarita,

You are looking for the max value of the parabola with vertex (0, 3). The largest value of y is the y-coordinate of the vertex.

4. ## Mush...

Originally Posted by Mush
Again... differentiate wrt y, set equal to zero, solve for x, and put x value back into original equation!

$\frac{dy}{dx} = -2x = 0$
Why did you reply using calculus?
This is an algebra 2 question.

5. ## ok...

Originally Posted by masters
Hello Magentarita,

You are looking for the max value of the parabola with vertex (0, 3). The largest value of y is the y-coordinate of the vertex.
So, basically we set x = 0 and simplify, right?