SOLUTION: Use a reference rectangle and the rule of fourths to draw an accurate sketch of the following function through at least one full cycle. y = –4 cos t y = 4 cos t please help

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Question 1079787: Use a reference rectangle and the rule of fourths to draw an accurate sketch of the following function through at least one full cycle.
y = –4 cos t
y = 4 cos t
please help me i dont know how to solve this to get an accurate sketch of the ff. function

Found 2 solutions by Boreal, MathLover1:
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
Few things to remember about cosine
Positive in Q1 and Q4.
At 45 degrees in those quadrants, it is sqrt(2)/2 and in the other two it is - sqrt(2)/2.
At 30 degrees in Q4 (300 deg from origin), it is 1/2, and again at 60 degrees. It is -1/2 at 120 and 240 degrees, 180 degrees apart from those two values
At 60 degrees (330 in Q4) and at 30 degrees in Q1, it is sqrt(3)/2. At 150 and 210 it is - sqrt (3)/2
The amplitude is 4, so it is the cosine graph increased by a factor of 4 in the vertical plane. This is graphed by radians.
graph%28300%2C300%2C-6%2C6%2C-5%2C5%2C4cos%28x%29%2C-4cos%28x%29%29
The - cos t is the one that is -4 at x=0.

Answer by MathLover1(20850) About Me  (Show Source):