K, this one I'm having trouble on. Please help! Precalc/trig problem. Click attached

Question

anonymous · Answer

attachment

hero · Answer

How many of these do you have? :P

anonymous · Answer

To be honest... Only a few more. But if you didn't notice already, math is my worst subject!

hero · Answer

Hint: let y = sin x

anonymous · Answer

here is my thought here y=sin x  if I am right it's 270 degrees I have no calc to do this on.

anonymous · Answer

That is what I got after taking what Hero said. Thank you for confirming.

anonymous · Answer

?? can you show in a drawing how got there? I am just checking myself..

hero · Answer

You let y = sin x so that you can have:

3y^2 + 2y - 1 = 0 

3y^2 + 3y - y - 1 = 0
3y(y + 1) - 1(y+1) = 0
(y+1)(3y-1) = 0

sin x + 1 = 0
3sin x - 1 = 0

anonymous · Answer

did you see the answer choices??

hero · Answer

Yeah, I saw them

anonymous · Answer

okay so when you take y=sinx and do what you did I came up with 270 degress is this right?

hero · Answer

How did you get that?

hero · Answer

I got x = -90 for one of them which I guess is the same as 270

hero · Answer

360 - 90 = 270

hero · Answer

Go Figure

anonymous · Answer

that is what I did in my head

hero · Answer

Trigonometrically, - 90degrees means the same as 270 degrees, but I'm not telling you anything you don't already know.

anonymous · Answer

-90 degrees in trig does sometimes throws me, I still have no clue why that happens..

hero · Answer

The negative just means "in the other direction" in trig

hero · Answer

or in the "reverse" direction

anonymous · Answer

oh yeah duh. man I am brain farting big time wow

anonymous · Answer

sorry

hero · Answer

You did it in your head which is commendable.

hero · Answer

Any thoughts @Ilovecharlie ?

anonymous · Answer

see in my head I knew 360-90 =270 but for the life of me I could not type it AURGH!!

hero · Answer

You did it in your head which is 1000x better than writing it. Why are you frustrated?

anonymous · Answer

I am majoring in Physics Engineering

hero · Answer

Well that's great! Good on you!

anonymous · Answer

good on here, but when I am in trig in college I doubt this will be good doing things like this in your head.

hero · Answer

Yeah, cause you have to show work on paper. But doing it in head is best. You just need a print out for your brain because it obviously functions like a computer.

anonymous · Answer

may be my brain ran out of ink. lol