00:03
This is problem number 21, and we're given a point's polar coordinates and asked to find the corresponding rectangular coordinates.
00:12
So to find rectangular coordinates xy, remember that to find x, we find r cosine theta, and for y, it's r sine theta, where our point has an r value of 2 and a theta value of 270 degrees.
00:32
So we can substitute those values in, and r cosine theta is 2, cosine, 270, and our sine theta is 2, sine 270.
00:45
Now at the end of the video, i'll show you how you can find the exact values for cosine and sine of 270, but for the moment, let's imagine that you know how to do that part, and the cosine of 270 is 0.
00:57
So for the x coordinate, we have 2 times 0, and the sine of 270 is negative 1, so our y coordinate is 2 times negative 1, simplify those, and we have 0 -2 as the rectangular coordinate pair for our point...