SOLUTION: How do you graph y=3cosx by finding the maximum & minimum. I know that the amplitude is 3 the period is 1 but my algebra book doesn't do a very good job on explaining how to find t

Algebra ->  Trigonometry-basics -> SOLUTION: How do you graph y=3cosx by finding the maximum & minimum. I know that the amplitude is 3 the period is 1 but my algebra book doesn't do a very good job on explaining how to find t      Log On


   

Question 703150: How do you graph y=3cosx by finding the maximum & minimum. I know that the amplitude is 3 the period is 1 but my algebra book doesn't do a very good job on explaining how to find them. I got a test tomorrow & I still don't understand it. Thanks.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Suppose the problem was +y+=+cos%28x%29+
As you vary +x+ from +x+=+0+ counterclockwise
to +x+=+2%2Api+, and +y+ varies from 1, 0, -1, 0, 1
At no point is it less than +-1+ or greater than +%2B1+
----------
Now if the problem is ++y+=+3%2Acos%28x%29+, and y varies
from 3, 0, -3, 0, 3
----------
The period is +2%2Api+ because I can say
+3%2Acos%28x%29++=+3%2Acos%28+x+%2B+2n%2Api+%29+ where +n+ can be
0, 1, 2 ,3 ...etc.