MathDB
Trigonometric System

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April 6, 2013
trigonometryAMCAMC 12

Problem Statement

Let aa and bb be real numbers such that sina+sinb=22\sin a+\sin b=\dfrac{\sqrt2}2 and cosa+cosb=62\cos a+\cos b=\dfrac{\sqrt6}2. Find sin(a+b)\sin(a+b).
<spanclass=latexbold>(A)</span>12<spanclass=latexbold>(B)</span>22<spanclass=latexbold>(C)</span>32<spanclass=latexbold>(D)</span>62<spanclass=latexbold>(E)</span>1<span class='latex-bold'>(A) </span>\dfrac12\qquad<span class='latex-bold'>(B) </span>\dfrac{\sqrt2}2\qquad<span class='latex-bold'>(C) </span>\dfrac{\sqrt3}2\qquad<span class='latex-bold'>(D) </span>\dfrac{\sqrt6}2\qquad<span class='latex-bold'>(E) </span>1