How do you graph #y = cos2x#?

1 Answer
Gió
Jul 1, 2015

This is a cossine function that gives you a graph similar to the "normal" cosine with amplitude #1# BUT period of #pi# only .

Explanation:

This is a cosine function with amplitude equal to #1# (it comes from the one "in front" of #cos# that is not written but it is there!) and period obtained from the #2# in front of #x# in the argument as:
#period=(2pi)/color(red)(2)=pi#.

This value of the period tells you that this is not the normal cosine but it is "squeezed" to fit an entire oscillation between #0# and #pi# instead of between #0# and #2pi# as the "normal" cosine.

Graphically:
#y=cos(2x)#
graph{cos(2x) [-10, 10, -5, 5]}

A "normal" cosine would look as:
#y=cos(x)#
graph{cos(x) [-10, 10, -5, 5]}

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