SOLUTION: I am having a really tough time understanding how this works. My teacher explained how this all breaks down, but I still do not understand how we arrive at the final part. Here

Algebra ->  Trigonometry-basics -> SOLUTION: I am having a really tough time understanding how this works. My teacher explained how this all breaks down, but I still do not understand how we arrive at the final part. Here      Log On


   

Question 1033745: I am having a really tough time understanding how this works.
My teacher explained how this all breaks down, but I still do not understand how we arrive at the final part.
Here are the examples I have:
+x+=+2+cos%28t%29+ when +x+=+0+
= +2+cos+%28t%29+=+0+
= +cos+%28t%29+=+0+
= +t+=+pi%2F2+
I am having a hard time understanding how it became +t+=+pi%2F2+ from the previous step.
AND
+x+=+2+cos+%28t%29+ when +x+=+2+
= +2+cos+%28t%29+=+2+
= +cos+%28t%29+=+1+
= +t+=+0+
I am having a hard time understanding how it became +t+=+0+ from the previous step.
For both of these, I am looking at a Unit Circle, but I just don't see what I am missing.
Help/explanation would be greatly appreciated! Thank you!
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
x is the value of a function, and t is the angle measure or variable input for the function. You are starting with x=2%2Acos%28t%29.

You are interested in finding t if x=0. You find your way to a step,
cos%28t%29=0.
At this stage, you must be acquainted with the meaning of cosine, and the common reference angles and the Unit Circle. No more mystery.

In fact, referring to the unit circle, t=pi%2F2 OR t=-pi%2F2.



Same basic concepts to do your second question.