# Determine Value of Trig Functions

My question is to determine the values of the primary and secondary tri functions at (-3,-4) on the terminal arm of an angle theta in standard position

Im just wondering how do u know which quadrant this point is in? I have assumed it is in quadrant 1. Then that means x=-3, y=-4, and r=5?

When determining values for trig functions for example lets say
$$\sin= \frac {opposite} {hypotenuse} = \frac {-4} {5}$$ is this the value they want me to determine or do I have to put it in decimals?

dextercioby
Homework Helper
IIRC,the point of coordinates x=-3,y=-4 is in the 3-rd quadrant.Its distance to the center is 5.

Can u take it from here??

Daniel.

yes just tell me how u know its in the third quadrant? and all I have to do is put opposite/hyp and then adj/hyp etc to determine the values for all the tri functions right?

http://www.mmsonline.com/mag_images/cnc9801e.gif [Broken]

Last edited by a moderator:
dextercioby
Homework Helper
aisha said:
yes just tell me how u know its in the third quadrant? and all I have to do is put opposite/hyp and then adj/hyp etc to determine the values for all the tri functions right?

BECAUSE THE COORDINATES OF THE POINT ARE BOTH NEGATIVE:If "x" is negative,then it's either in the II-nd or the III-rd quadrant.If "y" is negative it's either in the III-rd or the IV-th quadrant.

Figure out what happens if both are negative at the same time...

For the second part,"YES".

Daniel.

BobG