document.write( "Question 82694: simplify the expression: cscx(tan(-x))\r
\n" ); document.write( "\n" ); document.write( "simplify the expression: cotxcos(3.14/2-x)\r
\n" ); document.write( "\n" ); document.write( "verify the identity: cos^4x-sin^4x=cos^2x-sin^2x
\n" ); document.write( "
\n" ); document.write( "

Algebra.Com's Answer #59358 by kev82(151)\"\" \"About 
You can put this solution on YOUR website!
Hi,
\r
\n" ); document.write( "\n" ); document.write( "i'm very sorry if I'm wrong, but I get the impression you just want the answers, so I'm going to give some helpful advice instead. If you have tried it then please post where you're stuck.
\r
\n" ); document.write( "\n" ); document.write( "First question: For questions like this, I always recommend you go back to basics. Replace everything in terms of sine and cosine. Well, cosec=1/sin and tan=sin/cos. (You need to remember these!) I'm sure you can take it from there. Don't forget what sin(-x) and cos(-x) are.
\r
\n" ); document.write( "\n" ); document.write( "Second Question: The idea is the same as last time, write everything in terms of sines and cosines. If you don't know cot=cos/sin. However this time we need to get rid of that pi/2. See what you can do with the addition formula for cosine (you should also know this) .
\r
\n" ); document.write( "\n" ); document.write( "Third Question: I'm sure there are many ways to do this. My method is to write everything in terms of cos(2x). What do you get if you let A=B in the addition formula given above for cosine. can you combine this with the identity to get as a function of . let me know how you get on with this one because it's quite hard. If you get stuck post back with your working.
\r
\n" ); document.write( "\n" ); document.write( "Hope that helps,
\n" ); document.write( "Kev
\n" ); document.write( "
\n" );