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

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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
asked Feb 10, 2015 in TRIGONOMETRY by anonymous
reshown Feb 10, 2015 by goushi

1 Answer

0 votes

Step 1:

(a)

The expression is .

Apply Pythagorean identity .

.

Step 2:

(b)

The expression is .

Apply reciprocal identity image.

image

image.

Step 3:

(c)

The expression is image.

Apply reciprocal identity image.

image

image.

Step 4:

(d)

The expression is image.

Apply quotient identities image.

image.

image.

Solution:

(a) .

(b) image.

(c) image.

(d) image.

answered Feb 10, 2015 by Sammi Mentor

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