Do Homework - Brandon Frey- MyMathLab Pearson https://www.mathd.com/Student/PlayerHomework.aspx?homeworkld-44 Lab urses Homework: Section 7.7 Home se Home ewrk Score: 0 of 1 pt rse Documer 7.7.19 cussions ext and Video adebook Express the given sum or difference as a product of sines and/or cosines cos 30 + cos 94) cos 3 + cos 9tj (Simplify your answer, including any radicals. Use integers or fractions for any tudy Plan ools for Succes Purchase Option Course Tools Enter your answer in the answer box and then click Check Answer All parts showing Type here to search DeLL
We know that
cos A + cos B = 2*cos(A+B)/2*cos(A-B)/2
Then
cos3 + cos9 = 2*cos(3 + 9)/2*cos(3 - 9)/2 = 2*cos6*cos(-3) = 2*cos6*cos(3)
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