document.write( "Question 293364: hoe to find the exact value of cos(arcsin(-1/2) + arctan(2/3))= \n" ); document.write( "
Algebra.Com's Answer #211830 by Alan3354(69443)\"\" \"About 
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find the exact value of cos(arcsin(-1/2) + arctan(2/3))
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\n" ); document.write( "Plot the points and assign the angles A and B
\n" ); document.write( "A = arcsin(-1/2) = -30º
\n" ); document.write( "cos(A) = sqrt(3)/2
\n" ); document.write( "sin(A) = -1/2
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\n" ); document.write( "B = arctan(2/3)
\n" ); document.write( "gives the point (2,3), a distance of sqrt(13) from the Origin.
\n" ); document.write( "cos(B) = 3sqrt(13)/13
\n" ); document.write( "sin(B) = 2sqrt(13)/13
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\n" ); document.write( "cos(A+B) = cos(A)cos(B) - sin(A)sin(B)
\n" ); document.write( "= sqrt(3)/2 * 3sqrt(13)/13 - (-1/2)*2sqrt(13)/13
\n" ); document.write( "= \"3sqrt%2839%29%2F26+%2B+sqrt%2813%29%2F13\"
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\n" ); document.write( "or, = \"%28sqrt%2813%29%2F26%29%2A%283sqrt%283%29+%2B+2%29\"
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