PaRtZ Posted February 19, 2008 Report Share Posted February 19, 2008 (edited) Firstly I f*cking hate these things. biggest waste of time ever! Got to prove 1 + cot2x = cosec2xGot NO idea how to do. Just spent the last hour substituting what I know in and nothing turns out right. The more explained, the betterthanks Edited February 19, 2008 by PaRtZ Quote Link to comment Share on other sites More sharing options...
MattB Posted February 19, 2008 Report Share Posted February 19, 2008 Being doing these as well. Gimme a lil while and I'll give it ago.You not the only one who hates them either.Matt Quote Link to comment Share on other sites More sharing options...
PaRtZ Posted February 19, 2008 Author Report Share Posted February 19, 2008 I looked on wiki and it said you can derive it using just:cos2x + sin2x = 1tan x = sin x / cos xand the basic reciprocal functions Quote Link to comment Share on other sites More sharing options...
Davetrials Posted February 19, 2008 Report Share Posted February 19, 2008 (edited) is it cot2x1secx?*bran tumor* Edited February 19, 2008 by Davetrials Quote Link to comment Share on other sites More sharing options...
NVWOCI WVS Posted February 19, 2008 Report Share Posted February 19, 2008 I have the brain capacity of a 3 year old. Quote Link to comment Share on other sites More sharing options...
Davetrials Posted February 19, 2008 Report Share Posted February 19, 2008 are u having a f**king laugh.. that appears to be some complex shit right there? Quote Link to comment Share on other sites More sharing options...
NVWOCI WVS Posted February 19, 2008 Report Share Posted February 19, 2008 are u having a f**king laugh..yes, a little bit. Quote Link to comment Share on other sites More sharing options...
MattB Posted February 19, 2008 Report Share Posted February 19, 2008 Using the identity 1 + cot2x = cosec2x you can replace it with cosec2x.Giving you cosec2x = cosec2x.I left my bag at college but thats all i remember.Matt Quote Link to comment Share on other sites More sharing options...
PaRtZ Posted February 19, 2008 Author Report Share Posted February 19, 2008 Using the identity 1 + cot2x = cosec2x you can replace it with cosec2x.Giving you cosec2x = cosec2x.I left my bag at college but thats all i remember.Mattyeah the question is, prove it I think benjaminge has posted in daves spin off thread... Quote Link to comment Share on other sites More sharing options...
Krisboats Posted February 19, 2008 Report Share Posted February 19, 2008 Firstly I f*cking hate these things. biggest waste of time ever! Got to prove 1 + cot2x = cosec2xGot NO idea how to do. Just spent the last hour substituting what I know in and nothing turns out right. The more explained, the betterthanksWhat are the other functions? You need to either split cosec2x into seperate parts by proving that its made up of something else. like saying 2x+y=3 and as a seperate rule you know y=x2 so you substitue that in instead of y.You could also bring the cot over and divide cosec by cot, then follow it through splitting it up into sin/cos/tan and finding where it is on the corresponding graph maybe?Been a while since i did maths at this level Quote Link to comment Share on other sites More sharing options...
Will Arnold Posted February 19, 2008 Report Share Posted February 19, 2008 hmm, yeah was doing some of the these not so long ago!you have to use some basic trigonometric rules to re-arrange it, then you can see it in a way that makes more sence. if i had my trig solutions booklet with me i'd enlighten you bruv Quote Link to comment Share on other sites More sharing options...
Phatmike Posted February 20, 2008 Report Share Posted February 20, 2008 Aww man, can't believe I used to be able to do all these. Mike get dumb more since college.Good luck anyways matt. Quote Link to comment Share on other sites More sharing options...
mink Posted February 20, 2008 Report Share Posted February 20, 2008 I looked on wiki and it said you can derive it using just:cos2x + sin2x = 1tan x = sin x / cos xand the basic reciprocal functionsThis make any sense? Quote Link to comment Share on other sites More sharing options...
King C Posted February 20, 2008 Report Share Posted February 20, 2008 This make any sense?I've been doing these but I cant be bothered. Mink seems to have got it though. Quote Link to comment Share on other sites More sharing options...
Haz Posted February 20, 2008 Report Share Posted February 20, 2008 Aww man, can't believe I used to be able to do all these. Mike get dumb more since college.Good luck anyways matt. Werd. Quote Link to comment Share on other sites More sharing options...
PaRtZ Posted February 20, 2008 Author Report Share Posted February 20, 2008 This make any sense?Its just the last step, how do you get the sin2x cos2x ? All I can gather is you added together 1 / sin2x and cos2x / sin2x In which case I need to re-learn how to cross multiply again Answer me that and im sorted and thanks alot everyone else Quote Link to comment Share on other sites More sharing options...
Fuse Posted February 20, 2008 Report Share Posted February 20, 2008 The last step is just multiplying both sides by sin2x. The "1" then becomes sin2x and the cos2x/sin2x cancels leaving just cos2x. On the other side you'd have sin2x/sin2x which cancels to 1. Quote Link to comment Share on other sites More sharing options...
PaRtZ Posted February 20, 2008 Author Report Share Posted February 20, 2008 The last step is just multiplying both sides by sin2x. The "1" then becomes sin2x and the cos2x/sin2x cancels leaving just cos2x. On the other side you'd have sin2x/sin2x which cancels to 1.foooking lovely!!!!!Thank you soo much! Quote Link to comment Share on other sites More sharing options...
Fuse Posted February 20, 2008 Report Share Posted February 20, 2008 No problem, Mink did the hard work I remember doing this stuff a few years back but without my book of trig identities (which is sat in a box somewhere along with all my other college and uni work!) I wouldn't have been able to do it these days. Quote Link to comment Share on other sites More sharing options...
PaRtZ Posted February 20, 2008 Author Report Share Posted February 20, 2008 lol well thanks anywayAnd thanks Mink too, I almost forgot sorry! Quote Link to comment Share on other sites More sharing options...
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