¶ Spring 2021 AMC 12B Problem 13
Problem:
How many values of in the interval satisfy
Answer Choices:
A.
B.
C.
D.
E.
Solution:
We rearrange to get
We can graph two functions in this case:
Using transformation of functions, we know that is just a cosine function with amplitude 5 and period . Similarly, is just a sine function with amplitude and shifted unit downward:
So, we have solutions.
The problems on this page are the property of the MAA's American Mathematics Competitions