Graph y=4cos(x)
Problem
Solution
Identify the parent function and its properties. The base function is
y=cos(x) which has an amplitude of1 and a period of2*π Determine the amplitude of the given function. The coefficient
4 in front of the cosine function indicates a vertical stretch, making the amplitude|4|=4 Determine the period of the function. Since the coefficient of
x is1 the period remains2*π Identify key points for one full cycle starting from
x=0 The cosine function starts at its maximum value.
At
x=0 y=4*cos(0)=4 At
x=π/2 y=4*cos(π/2)=0 At
x=π y=4*cos(π)=−4 At
x=(3*π)/2 y=4*cos((3*π)/2)=0 At
x=2*π y=4*cos(2*π)=4
Sketch the graph by plotting these key points and connecting them with a smooth, wave-like curve that oscillates between
y=4 andy=−4
Final Answer
The graph is a cosine wave with an amplitude of
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