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You can put this solution on YOUR website!
this is a difference of squares on the left. I will write x instead of theta and use ctn rather than cot, but that won't affect the result.
\n" ); document.write( "csc^4 x-ctn^4 x=
\n" ); document.write( "(csc^2 x+ctn^2 x)(csc^2 x- ctn^2 x)=
\n" ); document.write( "convert to sin and cos forms, and first parentheses is
\n" ); document.write( "(1/sin^2 x)+ (cos^2 x/sin^2 x)=
\n" ); document.write( "(cos^2 x+ 1)/sin^2 x, putting it over a common denominator sin^2 x
\n" ); document.write( "The other parentheses is
\n" ); document.write( "(1/sin^2 x)- (cos^2 x/sin^2 x)
\n" ); document.write( "and that is
\n" ); document.write( "(1-cos^2 x)/sin^2 x
\n" ); document.write( "Their product is (cos^2 x+ 1)/sin^2 x*(1-cos^2 x)/sin^2 x.
\n" ); document.write( "But 1-cos^2x=sin^2 x
\n" ); document.write( "so the last part of the above is sin^2 x/sin^2 x or 1
\n" ); document.write( "The product is (cos^2 x+ 1)/sin^2 x
\n" ); document.write( "But sin^2 x= 1-cos^2 x
\n" ); document.write( "Therefore, the product above is (1+cos^2 x)/(1-cos^2 x) \n" ); document.write( "