Question

Given that cosθ = -12/13 and θ is in the second quadrant, find cscθ.

i tried using the chart you gave me but it doesnt have the right fuction for this question! ): please help!

Answer 1

@Kainui
-13/5
-13/12
13/12
13/5

Answer 2

Sure, so remember SOH CAH TOA? Use that and label this triangle.

Answer 3

yupp andd?

Answer 4

Well then you can just look at it and say, hey, I need to find csc(theta) right? So what's that? Look at the table and you'll see it's just 1/sin(theta) so that means since sine is just SOH, then if you do 1/sine you just switch from Opposite over Hypotenuse to Hypotenuse over Opposite for csc, which is cosecant. Since you labelled the triangle with cosine's Adjacent and Hypotenuse, you can use the pythagorean theorem to find the Opposite side so that you can make the ratio for cosecant -- which is just the upside-down version of sine.

Answer 5

ohhhh then its just an reciprocal of cosθ = -12/13??

Answer 6

Not quite, if they asked you to find sec(theta) then you would just find the reciprocal since secant is the reciprocal of cosine. But you have to do a little extra since cosecant is the reciprocal of sine, and you're given cosine.

Answer 7

If part of my explanation is just not making sense, just ask! I'm here to make sure you "get it" you know? I'm not a perfect explainer, so maybe I can explain it differently to make it make sense! =D

Answer 8

im trying to understand what you've explained while im solving my problems ): ughh but still you've been such a big help! thank you so much again for spending your time helping me!

Answer 9

but lastly, would the answer be -13/5?? ):

Answer 10

Almost, but I think the triangle I drew as an example was slightly misleading. The question says that the triangle is in the second quadrant, so it should really look like this:



So you know the negative sign has to go on the adjacent side, not the hypotenuse. So if you look at the triangle, the sides involved will be the hypotenuse and opposite, which are both positive numbers, so the number is positive.

Other than that, you're right!

Answer 11

@Kainui oh yay! you have the best explanations :D

Answer 12

Cool thanks! B)

Answer 13

omg then my answer is incorrect?? 0.0