1. Aug 26, 2004

Poweranimals

Does anyone know how to do this?

Let Ø be an angle in standard position. Name the quadrant in which the angle lies.

sin Ø > 0, cos Ø < 0

Last edited: Aug 26, 2004
2. Aug 27, 2004

Math Is Hard

Staff Emeritus
You could start by thinking about some angles that fit that description...
(just an idea)

3. Aug 27, 2004

Crumbles

Check out this diagram or the quadrants part of this site.

As you can see, you have 4 quadrants, one where ALL [sin, cos and tan] are positive [0 to 90 degrees], one where just sin is positive and cos and tan are negative [90 to 180 degrees], one where just tan is positive and sin and cos are negative [180 to 270 degrees] and one where just cos is positive and where sin and tan are negative [270 to 360 degrees].

Your question says sin Ø > 0, cos Ø < 0. This is basically saying the sin of your angle is positive and the cosine of your angle is negative. Now if you look at the diagram, you will see that sin Ø > 0, cos Ø < 0 is true in the sin quadrant because this is where sine is positive.

An easy way to remember those quadrants is by the first letter of this phrase, All Silly Teachers Cheat. Or if you want to be kind to teachers, Add Sugar To Coffee! This technique works going anti cloclwise from the 0 - 90 quadrant.

Last edited: Aug 27, 2004
4. Aug 27, 2004

Crumbles

Just a quick note, the 0-90 quadrant is usually referred to as the first quadrant. The 90-180 one as the second quadrant, the 180-270 one as the third quadrant and the 270 to 260 one as the fourth quadrant, as shown on this page.

5. Aug 27, 2004

Math Is Hard

Staff Emeritus
Back in my day it was:

All
Students
Take
Calculus

:tongue2:

6. Aug 27, 2004

Gokul43201

Staff Emeritus
Heck, I used All Silver Tea Cups !

7. Aug 27, 2004

Math Is Hard

Staff Emeritus
A little pretentious but I like it! :rofl:
It goes along nicely with Please Excuse My Dear Aunt Sally!