document.write( "Question 969502: Prove. (cotx-cscx)(cosx+1)=sinx \n" ); document.write( "
Algebra.Com's Answer #592376 by Boreal(15235)![]() ![]() You can put this solution on YOUR website! cot x=cos x/sin x; csc x=1/sinx\r \n" ); document.write( "\n" ); document.write( "Rewrite in terms of sin x and cos x\r \n" ); document.write( "\n" ); document.write( "(cos x/sin x)-(1/sin x) (cos x +1)\r \n" ); document.write( "\n" ); document.write( "There is a common denominator, sin x\r \n" ); document.write( "\n" ); document.write( "[(cos x-1)/sin x] (cos x +1). Now, multiply the first term by cos x and by +1\r \n" ); document.write( "\n" ); document.write( "{(cos^2 x-cos x)/sin x} + (cos x- 1)/sin x\r \n" ); document.write( "\n" ); document.write( "You have a common denominator of sin x\r \n" ); document.write( "\n" ); document.write( "[cos^2 x- cos x + cos x -1]/sin x\r \n" ); document.write( "\n" ); document.write( "In the numerator, the middle 2 terms disappear, and we have cos^2 x -1 left. But that is sin^2 x \n" ); document.write( "because sin^2 x + cos ^2 x =1\r \n" ); document.write( "\n" ); document.write( "we have sin^2 x/sin x . That equals sin x, which is the other side of the equation. \r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |