|
Stuck on a problem (that is probably dead easy -_-) but have no source of help, and, since its a 'proove that' question, no answer in the book... Although i guess ive already been given it.
Proove that cosh^2(x) + sinh^2(x) = cosh(2x)
Meh, more venting than asking for help i guess, cos its not that big of a problem, i just get frustrated when i cant figure out something and have no way of finding the asnwer, ive been so desperate ive even tried googling it, but no proofs of the rule seem to come up, just pages and pages that state it =[.
Fml.
I've also actually been playing some sc again lately after like, a year or longer break. At D+ atm with like 20-18 record or something, add me on iccup friends (xghpinder) if you're looking for someone to play with and chat about games afterwards. I wont be around til after this week however cos im home for the easter holidays =]
 
|
write cosh and sinh as their exponentials and simplify.
|
i do that and get to
1/4((e^x+e^-x)^2+(e^x-e^-x)^2)
and dont know how to proceed? 
|
taylor series, use them?
edit:
On April 16 2009 15:10 Ftrunkz wrote:i do that and get to 1/4((e^x+e^-x)^2+(e^x-e^-x)^2) and dont know how to proceed?
how about multiplying out the square?
|
expand out the squares to get 1/2(e^2x+e^-2x) which is cosh2x...
|
OH MY GOD epic fail by me, wowwwwwwwwwwwwwwwww.
bbl dropping science for an arts course.
lol, thx for pointing out the obvious for me guys 
|
hello ... google
Prove that cosh 2x = cosh2 x + sinh2 x.
Beginning with the right-hand side: cosh2 x + sinh2 x = (ex + e-x)2/4 + (ex - e-x)2/4 =
(e2x + 2 + e-2x)2 / 4 + (e2x - 2 + e-2x)2 / 4 = (e2x + 2 + e-2x + e2x - 2 + e-2x)/ 4 =
(2e2x + 2e-2x)/ 4 = (e2x + e-2x)/ 2 = cosh 2x.
|
lol thx paper  i got it now tho.
Wow, im actually embarassed that it didnt even occur to me to multiply the squares.. For every view this gets i guess its one extra person in the world that thinks im a retard ;P
|
On April 16 2009 15:19 Ftrunkz wrote:lol thx paper i got it now tho. Wow, im actually embarassed that it didnt even occur to me to multiply the squares.. For every view this gets i guess its one extra person in the world that thinks im a retard ;P
you got that right
|
|
|
|
|
|
EPT
