Find the exact value of the expression.cos 40° cos 20° - sin 40° sin 20°
A. 
B. 
C. 
D. 
Answer: D
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Decide whether or not the given equation is an identity.sin 
= 
A. Yes B. No
A child has an enormous jar in which she has been saving all of her spare change. In order to determine exactly how much money she has in the jar, she dumps all of the coins on the floor and counts them. Under the watchful eye of her mother, she counts 180 pennies, 120 nickels, 100 dimes, and 80 quarters.The sampling proportion in this survey is
A. 100%. B. 180/480. C. 80/480. D. unknown. E. none of these
Write the complex number in polar form. Express the argument ? in degrees, with 0 ? ? ? 360°.-5 - 5i
A. 10(cos 180° + i sin 180°) B. 5(cos 240° + i sin 240°) C. 10(cos 290° + i sin 290°) D. 10(cos 240° + i sin 240°)
Perform the indicated operations and simplify the result. Leave the answer in factored form.
A. 
B. 
C. 
D. 