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.Last year, nine employees of an electronics company retired. Their ages at retirement are listed below. Find the mean retirement age. Round your answer to the nearest tenth.
A. 57.1 B. 56.5 C. 58.0 D. 57.8
Solve the equation.-3a + 5 + 4a = 15 - 29
A. 19 B. -19 C. 49 D. -49
Provide an appropriate response.h(x) = -2x + 5a. Is the point (2, 1) on the graph of the function?b. If x = 3, what is h(x)? What point is on the graph of the function?c. If h(x) = 5, what is x? What point is on the graph of h?d. What is the zero of h?
A. a. yes
b. h(3) = -3; (3, -3)
c. x = -2; (-2, 5)
d. 5
B. a. yes
b. h(3) = -1; (3, -1)
c. x = 0; (0, 5)
d. 5
C. a. yes
b. h(3) = -1; (3, -1)
c. x = 0; (0, 5)
d. 
D. a. no
b. h(3) = -1; (3, -1)
c. x = -2; (-2, 5)
d. 
Determine whether or not the function is one-to-one.f(x) = 4x2 + x
A. No B. Yes