# Math Help - Quick Question

1. ## Quick Question

Ok im doing a problem and it includes finding the values of six trig functions...my question is if im given a angle [ 315 degrees ] and after finding the reference angle what numbers do i use? Do i use (checkmark 2 / 2 and checkmark 2 / 2??

2. Given: $\theta = 315^{\text{o}}$
Take note that this angle is in the fourth quadrant. This means that the only the cosine/secant of this angle is positive.

First, find the reference angle.

$\theta_{ref} = 360 - 315 = 45^{\text{o}}$

Then, write down the six trigonometric functions of the original angle:

$\sin{315} = -\sin{45}$

$\cos{315} = \cos{45}$

$\tan{315} = -\tan{45}$

$\csc{315} = -\csc{45}$

$\sec{315} = \sec{45}$

$\cot{315} = -\cot{45}$

I will leave the evaluation for you.

Extra:
• If angle is in first quadrant, all trigonometric functions are positive
• If angle is in second quadrant, only sine/cosecant are positive
• If angle is in third quadrant, only tangent/cotangent are positive
• If angle is in fourth quadrant, only cosine/secant are positive

3. Thats the part I dont quite understand. Since there was no given values besides the reference angle. wont a side be messing? or do i just do it over the x or y value?

4. For angles 30, 45, and 60, you can use the special 45-45-90 and 30-60-90 triangles:
Special right triangles - Wikipedia, the free encyclopedia

To find the value of the trigonometric functions of these angles.

5. omg thank you! lol thats what I meant in the begining with the checkmark 2 i forgot to take notes on this!