/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 49 Use the product-to-sum formulas ... [FREE SOLUTION] | 91Ó°ÊÓ

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Use the product-to-sum formulas to rewrite the product as a sum or difference. $$\sin 5 \theta \sin 3 \theta$$

Short Answer

Expert verified
\[\sin 5\theta \sin 3\theta = 0.5[\cos(2\theta) - \cos(8\theta)]\]

Step by step solution

01

Recognize the formula

The given expression is in the form of \(\sin(A) \sin(B)\). The product to sum formula that corresponds to this form is: \[2\sin A \sin B =\cos(A-B)- \cos(A+B)\] where A is 5θ and B is 3θ in our case.
02

Apply the formula

Replace the given values in the formula which leads to: \[2 \sin(5\theta)\sin(3\theta) = \cos(5\theta - 3\theta) - \cos(5\theta + 3\theta)\]
03

Simplify the expression

On simplifying the above expression, we find: \[2 \sin(5\theta)\sin(3\theta) = \cos(2\theta) - \cos(8\theta)\]. Therefore, \[\sin(5\theta) \sin(3\theta) = 0.5[\cos(2\theta) - \cos(8\theta)]\]

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