SOLUTION: Ok, so I have my Honors Algebra 2 FINAL tomorrow and there is this certain type of problem I just don't understand. No matter how many times I try these types of problems I just ca

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Question 123996: Ok, so I have my Honors Algebra 2 FINAL tomorrow and there is this certain type of problem I just don't understand. No matter how many times I try these types of problems I just can't seem to get them right. Could someone maybe explain to me how to do the following type of problem? That would be a huge help. I'm hoping that maybe a second explanation other than the one from my teacher will help me finally understand.
You could use this problem as an example.
Directions: Solve each equation for 0%3C=+%28theta%29%3C+2%28pi%29
-5cos%28theta%29+=+cos%28theta%29+-+3%28square+root%293
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Try this:
-5cos%28theta%29+=+cos%28theta%29-3sqrt%283%29 (I hope I got this right): Subtract cos%28theta%29from both sides.
-6cos%28theta%29+=+-3sqrt%283%29 Now divide both sides by -6.
cos%28theta%29+=+sqrt%283%29%2F2
Now you are looking for the angle theta whose cosine is sqrt%283%29%2F2 or:
theta+=+cos%5E%28-1%29%28sqrt%283%29%2F2%29 or
theta+=+arccos%28sqrt%283%29%2F2%29
theta+=+30degrees.
In radians: theta+=+%28pi%29%2F6Radians.
Check:(Degrees)
-5cos%28theta%29+=+cos%28theta%29-3sqrt%283%29 Substitute theta+=+30
-5cos%2830%29+=+cos%2830%29-3sqrt%283%29
-5%280.866%29+=+%280.866%29-3%281.732%29
-4.33+=+-4.33
Check: (Radians)
-5cos%28theta%29+-+cos%28theta%29-3sqrt%283%29 Substitutetheta+=+%28pi%29%2F6
-5cos%28%28pi%29%2F6%29+=+cos%28%28pi%29%2F6%29-3sqrt%283%29
-5%280.866%29+=+%280.866%29-3%281.732%29
-4.33+=+-4.33