Find each exact value if 0 < x < pi/2 and 0 < y < pi/2
\n" );
document.write( "Cos(x-y) if sinx= 7/25 and cosy= 2/3\r
\n" );
document.write( "\n" );
document.write( "This is what I have so far:
\n" );
document.write( "cosa•cosB+sina•sinB
\n" );
document.write( "(7/25)(2/3)+(7/25)(sqrt5/3)
\n" );
document.write( "14/75+7sqrt5/75
\n" );
document.write( "14+7sqrt5/75\r
\n" );
document.write( "\n" );
document.write( "I'm not sure if I'm finished with the problem or if I have more steps or if I have just done the problem completely wrong. The answer doesn't match the key so I'm curious as to what I'm doing wrong. Thank you!
\n" );
document.write( "Find each exact value if 
\r\n" );
document.write( "
\r\n" );
document.write( "\r\n" );
document.write( "cos (A - B) = cos A cos B + sin A sin B ---- Difference of 2 angles' formula\r\n" );
document.write( "cos (x - y) = cos x cos y + sin x sin y ---- Replacing A with x, and B with y \r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "It's obvious that we need cos x and sin y\r\n" );
document.write( "
\r\n" );
document.write( "We see that a 7-24-25 Pythag triple ensues, and therefore, x = 24\r\n" );
document.write( "We now have: 
\r\n" );
document.write( "\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "
_____
\r\n" );
document.write( "We now have: 
\r\n" );
document.write( "\r\n" );
document.write( "cos (x - y) = cos x cos y + sin x sin y now becomes: \r\n" );
document.write( "cos (x - y) = 
------- Substituting 
\r\n" );
document.write( "Up to this point, you seem to have gotten 
, but 
.\r\n" );
document.write( "You should be able to complete it, now that you know where your mistake was.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Note that since it was stated that: , the angles are in the 1st quadrant.
\n" );
document.write( "![\"\"](\"/images/stars/stars-13.gif\")
