solve the following for the principal values of the indicated variable.
3cosx-1=2

Question

solve the following for the principal values of the indicated variable.
3cosx-1=2

ganeshie8 · Answer

isolate cosx first

anonymous · Answer

okay..but how do i get rid of it?

anonymous · Answer

divide by cos?

ganeshie8 · Answer

step by step

add +1 both sides

anonymous · Answer

i got that..cosx = 1

ganeshie8 · Answer

great! now what is principal value ?

anonymous · Answer

idk..lol

ganeshie8 · Answer

let me google... i dont remember either lol

anonymous · Answer

cosine of what angle gives 1 ?

anonymous · Answer

adj. over hyp.

anonymous · Answer

but..idk...

anonymous · Answer

here.. use the unit circle... page 3 http://tutorial.math.lamar.edu/pdf/Trig_Cheat_Sheet.pdf

anonymous · Answer

i dont understand that..

anonymous · Answer

oh.... sorry, you have'nt used the unit circle yet?

anonymous · Answer

i have..but im so frustrated with this crap..i don't feeling like trying to comprehend that...i've never used it for this..

anonymous · Answer

my apologies.... i didn't mean to offend u...

anonymous · Answer

you didn't..just tell me what the next step is

anonymous · Answer

let's just use your definition of cosine then:

$$\huge cos(\theta)=\frac{adjacent}{hypotenuse}=1 $$
the only time this can occur is when the adjacent side is the same length as the hypotenuse.  this means the angle is 0.  so cos(0)=1.  the principal value is 0