(a)

Consider .

Divide each side by .

Cancel common terms.

.

Thus, .

(b)

The equation is .

Let the functions are and .

Draw a coordinate plane.

Graph the functions and in the same window in the interval .

Observe the above graph :

The two functions and intersects at and in the interval .

(c)

On the unit circle refers to the - coordinate.

Here the - coordinate is at and .

On the unit circle refers to the - coordinate.

The - coordinate is at and   at .

Draw a coordinate plane.

Plot the points and on the unit circle.

Graph :

(d)

The equation is .

Let the functions are and .

Draw a coordinate plane.

Graph the functions and in the same window in the interval .

Observe the above graph :

The two functions and intersects at , , and in the interval .

(e)

Consider .

The general solution of is , where is an integer.

.

Thus, the solution is , where is an integer.

(a).

.

(b).

Graph of the functions and in the interval .

The two functions and intersects at  and in the interval .

(c).

The points and on the unit circle is :

(d)

Graph of the functions and in the interval .

The two functions and intersects at, , and in the interval .

(e)

The solution is , where is an integer.