Answer
$2((\cos(4x)-\cos(10x))$
Work Step by Step
We know that $\sin A\sin B=0.5((\cos(A-B)-\cos(A+B))$, hence here $4\sin 7x\sin 3x=2((\cos(4x)-\cos(10x))$
Trigonometry 7th Edition
by McKeague, Charles P.; Turner, Mark D.
Published by
Cengage Learning
ISBN 10:
1111826854
ISBN 13:
978-1-11182-685-7
Chapters 1-6 - Cumulative Test - Page 359: 26
Update this answer!
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.
