Sum and Difference Identities

Practice: Sum & Difference Identities


Determine the exact value for cos(A+B)\cos(\text{A}+\text{B}) if cosA=25\cos{\text{A}}=\dfrac{2}{5} and sinB=37\sin{\text{B}}=\dfrac{3}{7}. Assume & B\angle{\text{A}}~\&~\angle{\text{B}} are both in quadrant I.
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More Sum & Difference Identities Questions: