Establish the identity.cos(x - y) - cos(x + y) = 2 sin x sin y
What will be an ideal response?
cos (x - y) - cos (x + y) = cos x cos y + sin x sin y - ( cos x cos y - sin x sin y) = 2 sin x sin y.
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The floor of a lake slopes downward in a straight line. The depth 27 feet from shore is 16 feet. At what distance from shore is the depth 40 feet? ?
A. 67.50 feet B. 24.52 feet C. 23.70 feet D. 67.67 feet
Find the volume of the solid generated by revolving the region bounded by the given lines and curves about the 
. y = x2 + 3, y = 2x + 3
A. 
?
B. 
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C. 
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D. 8?
Solve the problem.The winner of the 1998 Peoria 500 (mile) race was Serge Bologna, with an average rate of 175.786 mi per hr. What was his time (to the nearest thousandth of an hour)?
A. 0.786 hr B. 12.844 hr C. 2.844 hr D. 2.919 hr
Graph the circle whose radius is r and whose center is (h, k). r = 2; (h, k) = (0, 1)
A. 
B. 
C. 
D. 