Question

cosine theta of 2 is in what quadrant?

Answer 1

Just cos(2)?

Answer 2

cosine theta =2.. I'm trying to figure out how to put it into a general solution. the reference angle for this would be -pi/3 correct?

Answer 3

Well, it'd be undefined. Sin and cos only have a range of [-1,1]. You would not ever get an answer of 2. If you want to check, then you can say that if cos(theta) = 2, then cos^-1(2) = theta. But when you do that you'll see undefined.

Answer 4

oh! i see it now. I thought i had to give an answer even if i got an error on the calculator. The problem i'm looking at is 2cos^2theta-(5costheta)+2=0 and they want me to give the general and specific solution. so far, i have 5pi/3+2pik and pi/3+2pik as the possible general solutions. can you please double check my work?

Answer 5

That's what I get. As for the second factor where you get cos(theta) = 2, those are simply no solutions. It'd be the same as if you factored some polynomial and you got (x-4)(x+4)(x^2+9). You can get-4 and 4 for the firsttwo, but theres nothing you can do without imaginary numbersfor the last one. Same thing heere, you have the two answers + 2kpi like you solved for and thatsit.

Answer 6

Thank you! :) best response!

Answer 7

Good luck!

Answer 8

Thank you :)