Answer:
The slope is 3/4
Step-by-step explanation:
Mean: so basically you add up all the numbers (5+12+1+5+7=30) and divide the sum (30) with how many numbers there are (5) so 30/5=6
mode: mode is numbers repeated, since there are two 5's it is the mode (you may also have multiple modes)
The main identity you need is the double angle one for cosine:

We get

Expand the numerator to apply the identity again:




Finally, make use of the product identity for cosine:

so that ultimately,

