document.write( "Question 1170546: Using a double-angle or half-angle formula to simplify the given expressions.
\n" ); document.write( "if cos^2(25∘)−sin^2(25∘)=cos(A∘) then A= . If cos^2(9x)−sin^2(9x)=cos(B) then B= . I have tried cos(50) for cos^2(25 deg)-sin^2(25deg)=cos (A deg).
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Algebra.Com's Answer #795394 by greenestamps(13216) $\"\"$ $\"About$

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\n" ); document.write( "The double angle formula is

\n" ); document.write( " $\"cos%28x%29%5E2-sin%28x%29%5E2+=+cos%282x%29\"$

\n" ); document.write( "So

\n" ); document.write( " $\"cos%2825%29%5E2-sin%2825%29%5E2+=+cos%2850%29\"$

\n" ); document.write( " $\"cos%289x%29%5E2-sin%289x%29%5E2+=+cos%2818x%29\"$

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