document.write( "Question 722263: sin (x+ 1/2 pi)=0 \n" ); document.write( "

Algebra.Com's Answer #442703 by DrBeeee(684) $\"\"$ $\"About$

You can put this solution on YOUR website!
The quick answer is
\n" ); document.write( "(1) sin(x+90) = cos(x)
\n" ); document.write( "The longer answer can be obtained the trig identity for the sum of two angles.
\n" ); document.write( "(2) sin(a+b) = sin(a)*cos(b) + cos(a)*sin(b)
\n" ); document.write( "Use x for a and 90 for b we get
\n" ); document.write( "(3) sin(x+90) = sin(x)*cos(90) + cos(x)*sin(90) or
\n" ); document.write( "(4) sin(x+90) = sin(x)*0 + cos(x)*1 or
\n" ); document.write( "(5) sin(x+90) = cos(x) \n" ); document.write( "

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