<p>in the polar coordinate system, if x = rcos and y = rsin, if you want to go clockwise, what changes to negative? both x and y, only x, only y?</p>
<p>and do we need to know how to do this for the ap calc bc exam?</p>
<p>thanks for any help i can get=)</p>
<p>It’s been a long time since I’ve done polar coordinates, but my understanding is that when looking at x = rcos(theta) and y = rsin(theta), if theta is positive, you’re measuring the angle from a counter-clockwise direction, and if theta is negative, you’re measuring the angle from a clockwise direction.</p>
<p>Thus, I’m thinking the answer to your question is, it depends on the angle whether x or y will change at all, but theta definitely changes signs.</p>
<p>For instance, if you want to move 11pi/6 radians clockwise, that’s an equivalent “position” to moving pi/6 radians counter-clockwise from the x-axis, because rcos(-11pi/6) = rcos(pi/6) and rsin(-11pi/6) = rsin(pi/6).</p>
<p>As for whether you need to know this for the BC exam, I’m not very familiar with the BC exam (I’ve only ever taught AB), but I would guess if you need to know polar coordinates at all, you would probably need to know how to do this.</p>
<p>With apologies in advance for any misinformation in this post that is the result of misremembering my BC calculus. :)</p>