Consider the equation $y=\cos x$`y`=`c``o``s``x`.

a

Using the fact that $\cos60^\circ=\frac{1}{2}$`c``o``s`60°=12, what is the value of $\cos120^\circ$`c``o``s`120°?

b

Using the fact that $\cos60^\circ=\frac{1}{2}$`c``o``s`60°=12, what is the value of $\cos240^\circ$`c``o``s`240°?

c

Using the fact that $\cos60^\circ=\frac{1}{2}$`c``o``s`60°=12, what is the value of $\cos300^\circ$`c``o``s`300°?

d

Complete the table of values, giving answers in exact form.

$x$x |
$0$0 | $60^\circ$60° | $90^\circ$90° | $120^\circ$120° | $180^\circ$180° | $240^\circ$240° | $270^\circ$270° | $300^\circ$300° | $360^\circ$360° |
---|---|---|---|---|---|---|---|---|---|

$\cos x$cosx |
$\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ | $\editable{}$ |

e

Plot the graph of $y=\cos x$`y`=`c``o``s``x`.

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Easy

Approx 5 minutes

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