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 = cos(4t)

Algebra ->  Graphs -> 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 = cos(4t)       Log On


   



Question 1083715: 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 = cos(4t)

Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
y = cos(4t) has a frequency of 4.

period = 2pi / frequency = 2pi / 4 = 2pi/4 = pi/2.

the full cycle of the cosine function of y = cos(4t) goes from 0 to pi/2.

if you break the period into quarters, you will get quarter periods of pi/2 / 4 = pi/8.

the function starts at x = 0
the first quarter ends at pi/8
the second quarter ends at 2pi/8
the third quarter ends at 3pi/8
the fourth quarter ends at 4pi/8

simplify the fractions and you get:

the function starts at x = 0
the first quarter ends at pi/8
the second quarter ends at pi/4
the third quarter ends at 3pi/8
the fourth quarter ends at pi/2

your rectangle has vertical sides at x = 0 and x = pi/2.

your rectangle has horizontal sides at y = 1 and y = -1.

here's the graph of cos(4x).

x is used instead of 5 to satisfy the graphing software.

$$$

here's a reference on graphing of sine and cosine functions.

http://www.purplemath.com/modules/grphtrig.htm