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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Solve the problem.Let u = 6i + j, v = i + j, and w = i - j. Find scalars a and b such that u = av + bw.
A. 6v + w B. 0.2857 v + 0.4000 w C. 3.500 v + 2.500w D. 6v - w
Sunlight is a mixture of all colors. When sunlight passes through water, the water absorbs different colors at different rates, as shown in the illustration below. Green light penetrates 4 times deeper than red light. Express this depth as a signed number. How far does green light penetrate?
__________ ft.
Fill in the blank(s) with the appropriate word(s).
Solve.Alan's yard is rectangular and measures 14.1 meters by 15.7 meters. Maria's yard is rectangular and measures 36.9 meters by 48.4 meters. How much greater is the area of Maria's yard than the area of Alan's yard?
A. 55.5 m2 B. 15,645.9 m2 C. 1564.59 m2 D. 2007.33 m2
Solve the problem.Sue drove her car 235 miles in January, 476 miles in February, and 398 miles in March. If her average mileage for the four months from January to April is to be at least 362 miles, how many miles must she drive in April?
A. at least 368 miles B. at most 339 miles C. at most 362 miles D. at least 339 miles