SOLUTION: Which expression is equivalent to cos(1.4x) − cos(0.6x)? a. -2sin x sin(0.4x) b. 2sin x sin(0.4x) c. -2cos x cos(0.4x) d. 2cos x cos(0.4x)

SOLUTION: Which expression is equivalent to cos(1.4x) − cos(0.6x)? a. -2sin x sin(0.4x) b. 2sin x sin(0.4x) c. -2cos x cos(0.4x) d. 2cos x cos(0.4x)

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Question 1172445: Which expression is equivalent to cos(1.4x) − cos(0.6x)?
a. -2sin x sin(0.4x)
b. 2sin x sin(0.4x)
c. -2cos x cos(0.4x)
d. 2cos x cos(0.4x)
Answer by math_tutor2020(3817) (Show Source): You can put this solution on YOUR website!

The trig identity we can use is

In this case,
A = 1.4x
B = 0.6x

Answer: Choice A
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