$\"\"$

(a)

The function is $\"\"$ .

Product-to-sum formulas : $\"\"$ .

$\"\"$

The product $\"\"$ can be written as a sum of $\"\"$ .

$\"\"$

(b)

The method of adding $\"\"$ - coordinates :

The function is $\"\"$ and the interval is $\"\"$ .

Consider the composite functions as $\"\"$ and $\"\"$ .

Make a table of values in the interval $\"\"$ :

\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \

$\"\"$

Graph :

(1) Draw the coordinate plane.

(2) Plot the points.

(3) Connect the points with a smooth curve.

$\"\"$ .

$\"\"$

(a) $\"\"$ .

(b) The graph of $\"\"$ :

$\"\"$ .