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#10626 Re: Exercises » What do you think? » 2011-06-27 07:34:57

i came to the problem the wrong way.i thought that i could find all the possibilities for a+b=c+d<=100 without any restrictions and then subtract the ones that include a,b,c or d>50.but that doesn't work.

#10628 Re: Exercises » What do you think? » 2011-06-27 07:08:40

hi bobbym

is the case a=1,b=2 the same as the case a=2 and b=1?

#10629 Re: Exercises » What do you think? » 2011-06-27 06:47:23

hi bobbym

Is one of those definitely the answer?

#10630 Re: Exercises » Limits! » 2011-06-27 06:41:34

hi gAr

I still can't seem to get it

All I got is the given expression is the same as

and

#10631 Re: Exercises » Limits! » 2011-06-27 06:05:45

I'm not sure i know how to do this one but it shoud be e^(1/6).

#10632 Re: Exercises » Limits! » 2011-06-27 05:55:07

hi gAr

thanks for opening the topic!
I needed this.

#10633 Re: Help Me ! » Solving systems of equations using Substitution method and elimination » 2011-06-27 05:44:18

hi zee-f

you should learn when it's better to use substitution method.for example , in 12) its easier just to substitute x from the second equation into the first one.

#10634 Re: Exercises » Is this cool with you? » 2011-06-27 05:13:24

These problems are very cool but i wish there were more problems on limits.

#10635 Re: Exercises » Is this cool with you? » 2011-06-27 04:56:18

It's probably wrong.gAr did it the same way and got it correct i might have added binom{20}{10} twice.

#10641 This is Cool » Trig Functions » 2011-06-27 02:59:16

anonimnystefy
Replies: 6

hi all

before i post about the trig functions i would just like to notice that this thread doesn't have a sticky.

now for the trig functions:
First there are some well-known trig functions:
sin
cos
tan(tg)
cot(ctg)
and their inverse functions:
arcsin
arccos
arctan(arctg)
arccot(arcctg)
Then there are some less known:
sec
cosec(csc)
arcsec
arccosec(arccsc)
And there are the least known ones like:
versin(vers,ver)
vercosin
coversin(cvs)
covercosine
haversin
havercosin
hacoversin
hacovercosine(the trig function with the longest name)
exsec
excsc(excosec)
crd(with full name of chord)

Wiki link:http://en.wikipedia.org/wiki/List_of_tr … identities

EDIT:What i forgot to mention are the hyperbolic functions:
sinh,
cosh,
tanh,
coth,
sh,
csch.

#10642 Re: Help Me ! » another question to check please » 2011-06-27 02:42:36

MIF stands for MathIsFun which is the name of the administrator of the forum and the name of the forum itself.

#10643 Re: Jai Ganesh's Puzzles » Trigonometry » 2011-06-27 02:31:41

hi ganesh

T#7 θ=60°

T #8 I got x=√2

#10644 Re: Jai Ganesh's Puzzles » Number Theory » 2011-06-27 02:23:07

correct.yeah actually every number of the form 13m or 13m+1.

#10645 Re: Help Me ! » Solving systems of equations using Substitution method and elimination » 2011-06-27 02:06:42

hi zee-f

if you would like to do this using the elimination than it would be like this:

#10647 Re: Help Me ! » another question to check please » 2011-06-27 01:54:12

I agree with bobbym.I think you are right, silverpuma.

#10648 Re: Help Me ! » Solving systems of equations using Substitution method and elimination » 2011-06-27 01:51:31

hi zee-f

This is how post #18 would look with LaTeX:

Much neater.

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