Question

Use the properties of trigonometric functions to find the exact value of the expressions.?

a) sin^240degrees + cos^2 40degrees
b)tan10degreescot10degrees
c)cos400degrees • sec400degrees
d) cot20degrees - cos20degrees/sin20degrees

Answer 1

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) .