binomial no calc

[TrueTears]

Exactly the same principle as how I did , try it and if you don't get it, I'll write up my working

[lacoste]

no wait i get it now, thanks man!! subing the 'x^2 in' cheers, we do that for all the tricky q's? yeh where theres an x at the bottom

[TrueTears]

no wait i get it now, thanks man!! subing the 'x^2 in' cheers, we do that for all the tricky q's? yeh where theres an x at the bottom

yeah but if you have basic equations which you can take a 'x' out and have a linear factor inside, then don't bother with substitution. But that question, no matter how much you manipulated it, you can never get a linear expression. So just use substitution

[lacoste]

It didnt work, i tried 3rd term and fifth row, switched both of the terms and used a calc to check and got 720/x
and 1080x

[lacoste]

how do i do the quick indices check, i havent fully understood it?

can someone please explain?

[TrueTears]

It didnt work, i tried 3rd term and fifth row, switched both of the terms and used a calc to check and got 720/x
and 1080x

oh damn, I'm beginning to have doubts about my method now lol

Frankly I am stomped atm, I don't see how you can work out the coefficient of without expanding... hmm maybe dekoyl or mao can help

[dekoyl]

Okay um I'll have a go.

Possible combo is only .

So looking at Pascal's triangle.





So coefficient is 810.

Is this right? I'm not sure how to do it without expanding o_O

Edit: Just checked on calc after numerous syntax errors =S. Should be right

[TrueTears]

I suggest dekoyl's method, works perfectly.

[lacoste]

thats right dekoyl but how does (kx^4)/x^3 relate to pascals triangle, where do you look in the triangle?

[dekoyl]

thats right dekoyl but how does (kx^4)/x^3 relate to pascals triangle, where do you look in the triangle?

On the previous page I bolded the row I looked at (1,5,...5,1)
is just a constant. I say because for this question you posted, there will not be a coefficient in the denominator.
I really suck at explaining =P Maybe someone more articulate can explain.

[lacoste]

combo is only . <<< I understand this now, your just making anything equal to x^3

"So looking at Pascal's triangle."

What do you mean by look at pascals triange regarding the above of .

where do u go to pascals to get nCr(5,1)?