document.write( "Question 1193960: For positive acute angles A and B,, it is known that sin A=9/41 and cos B=3/5 \r
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\n" ); document.write( " Find the value of cos (A-B) in simplest form. I know that sin A =9/41, 40/41 by drawing a triangle for help me to understand how to set up.
\n" ); document.write( " Robbin \n" ); document.write( "

Algebra.Com's Answer #826115 by MathTherapy(10553) $\"\"$ $\"About$

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\n" ); document.write( "For positive acute angles A and B,, it is known that sin A=9/41 and cos B=3/5 \r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( " Find the value of cos (A-B) in simplest form. I know that sin A =9/41, 40/41 by drawing a triangle for help me to understand how to set up.
\n" ); document.write( " Robbin
\n" ); document.write( "

cos (A - B) = cos A cos B + sin A sin B\r\n" );
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document.write( "Based on the above, you'll need cos A and sin B, since cos B and sin A were given.\r\n" );
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document.write( "          As  we can see that x, or the adjacent (A) side MUST be 40 since this is a 9-40-41 Pythagorean Triple. \r\n" );
document.write( "We then get: \r\n" );
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document.write( "          As  we can see that y, or the opposite (O) side MUST be 4 since this is a 3-4-5 Pythagorean Triple. \r\n" );
document.write( "We then get: \r\n" );
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document.write( "          \r\n" );
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