Which quadrant does theta lie in

Next page - Content - The sine and cosine rules. Content The four quadrants The coordinate axes divide the plane into four quadrants, labelled first , second , third and fourth as shown. Detailed description of diagram Related angles In the module Further trigonometry Year 10 , we saw that we could relate the sine and cosine of an angle in the second, third or fourth quadrant to that of a related angle in the first quadrant. Active 2 years ago. Viewed times. Taussig Jay Aherkar Jay Aherkar 11 2 2 bronze badges.

They don't lie in a quadrant. Add a comment. Active Oldest Votes. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Play Math Ball ». IntMath f orum ». An obtuse angle in standard position. How is this different to the definitions we already met in section 2, Sine, Cosine, Tangent and the Reciprocal Ratios? The only difference is that now x or y or both can be negative because our angle can now be in any quadrant.

It follows that the trigonometric ratios can turn out to be negative or positive. Let's see how the trigonometric ratios are defined using a particular example. Example of a trig ratio where the angle is greater than 90 o. Observe for the example above, that our angle was in the second quadrant. Also notice that in the second quadrant, the y -value is positive.

In the second quadrant, x is always negative. We use this diagram to remember what ratios are positive in each quadrant. We can remember it using:. Drag the point P around the curve into all 4 quadrants and observe the sin, cos and tan ratios that result.