### Home > CALC > Chapter 8 > Lesson 8.1.3 > Problem 8-28

Regarding horizontal or vertical rectangles... Is there a top function and a bottom function?

Or, is there a left-most function and a right-most function?

If it's the former, use vertical rectangles (and keep the equations written in *y* = ______________ form).

If it's the later, use horizontal rectangles (and keep the equations written as *x* = __________________ form).

Regarding the graph of *x* = − *y*² + 4...

In order to visualize this graph, you should not have to rewrite the equation in *y* = ___________________ form.

You should know that it will look like a sleeping (sideways) parabola with vertex at *x* = 4.

The negative indicates that the parabola opens to the left.

Might as well be consistent and write the first function as *x* = ______________ as well.

Regarding horizontal or vertical rectangles...

Refer to the hint in part (a).