Step 1:

(a)

The expression is .

Apply Pythagorean identity .

.

Step 2:

(b)

The expression is . \ \

Apply reciprocal identity . \ \

.

Step 3: \ \

(c) \ \

The expression is . \ \

Apply reciprocal identity .

.

Step 4: \ \

(d) \ \

The expression is . \ \

Apply quotient identities . \ \

.

.

Solution: \ \

(a) .

(b) .

(c) .

(d) . \ \