document.write( "Question 980776: Use the sum and differences formulas to prove the result of cos t = sin (t+pi/2).
\n" ); document.write( "(Hint: Let θ= t and let phi = pi/2. See what sin(t+pi/2) equals.) \r
\n" ); document.write( "\n" ); document.write( "Can you please show me how to do this problem? Thank you. \n" ); document.write( "

Algebra.Com's Answer #601841 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"sin%28x%2By%29=sin%28x%29cos%28y%29%2Bcos%28x%29sin%28y%29\"$
\n" ); document.write( "Now substitute,
\n" ); document.write( " $\"x=t\"$
\n" ); document.write( "and
\n" ); document.write( " $\"y=pi%2F2\"$
\n" ); document.write( " $\"sin%28t%2Bpi%2F2%29=sin%28t%29%2Acos%28pi%2F2%29%2Bcos%28t%29%2Asin%28pi%2F2%29\"$
\n" ); document.write( "Now simplify. \n" ); document.write( "

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