# 10.1 Graphs of `y` = `a` sin `x` and `y` = `a` cos `x`

**Graphs of $y\hspace{0.17em}=\hspace{0.17em}\mathrm{sin}\text{}x$ and $y\hspace{0.17em}=\hspace{0.17em}a\text{}\mathrm{cos}\text{}x$ • Amplitude • Graphs of $y\hspace{0.17em}=\hspace{0.17em}a\text{}\mathrm{sin}\text{}x$ and $y\hspace{0.17em}=\hspace{0.17em}a\text{}\mathrm{cos}\text{}x$**

When plotting and sketching the graphs of the trigonometric functions, it is normal to *express the angle in radians.* By using radians, both the independent variable and the dependent variable are real numbers. If necessary, review Section 8.3 on radian measure of angles.

# NOTE

[Therefore, it is necessary to be able to readily use angles expressed in radians.]

In this section, the graphs of the sine and cosine functions are shown. We begin by making a table of values of `x` and `y` for the function $y\hspace{0.17em}=\hspace{0.17em}\mathrm{sin}\text{}x\hspace{0.17em},\hspace{0.17em}$ where `x` and `y` are used in the standard way as the *independent variable* and *dependent variable.* We plot the ...

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