Question

Check my answers? Pre Calc help? The question is:
2. The polar coordinates of a point are given. Find the rectangular coordinates of each point.
a. (5,(π / 4))
b. (-2,(π / 6))

The answers I got are:
a. (4.99,0.27)
b. (-1.99, -0.11)


Am I right?

Answer 1

Let's focus on the first problem:

a. (5,(π / 4))

Here, the radius, r, is 5, and the central angle is Pi/4 (or 45 degrees). You might find it helpful to draw this situation.

Recall that in polar coordinates, x = r cos theta and y = r sin theta.

Try it. You'll see that r cos theta does not result in 4.99 in this case.

Seriously: Ask yourself: what are polar coordinates, really? and what are rectangular (or cartesian) coordinates? How are the two coordinate systems related?