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Ch. 2 - Graphs of the Trigonometric Functions; Inverse Trigonometric Functions
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601Non è quello che usi tu?Cambia libro di testo
Capitolo 2, Problema 64

In Exercises 61–66, use the method of adding y-coordinates to graph each function for 0 ≤ x ≤ 2π. y = cos x + cos 2x

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Identify the two functions involved: \(y_1 = \cos x\) and \(y_2 = \cos 2x\). We will graph each separately first for \(0 \leq x \leq 2\pi\).
Create a table of values for \(y_1 = \cos x\) by choosing several \(x\) values between \(0\) and \(2\pi\) (for example, \(0\), \(\frac{\pi}{2}\), \(\pi\), \(\frac{3\pi}{2}\), \(2\pi\)) and calculate the corresponding \(y_1\) values.
Similarly, create a table of values for \(y_2 = \cos 2x\) using the same \(x\) values, noting that the frequency is doubled, so the function completes two full cycles between \(0\) and \(2\pi\).
For each \(x\) value, add the corresponding \(y\)-coordinates from \(y_1\) and \(y_2\) to find the combined function value: \(y = \cos x + \cos 2x\).
Plot the points \((x, y)\) on the coordinate plane and connect them smoothly to graph the function \(y = \cos x + \cos 2x\) over the interval \(0 \leq x \leq 2\pi\).

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