Thread: Binomial theorem check

hey guys, just need to check if my working out and solution is correct.

Find the coefficient of in

My solution

So I started off by separating both brackets into 2 separate equations.

1.
2.

Now I find the coefficient of in equation 1 and I find the coefficient of in equation 2.

So:

now:

1. =

2. =

So now adding both up:

Solution:

Hello jvignacio

Originally Posted by jvignacio

hey guys, just need to check if my working out and solution is correct.

Find the coefficient of in

My solution

So I started off by separating both brackets into 2 separate equations.

1.
2.

Now I find the coefficient of in equation 1 and I find the coefficient of in equation 2.

So:

now:

1. =

2. =

So now adding both up:

Solution:

Your method is fine, but you have found the coefficient of in (1) and in (2).

You need to write the terms the other way around:

The term in is now:

Now you can put and respectively.

Grandad

Originally Posted by Grandad

Hello jvignacioYour method is fine, but you have found the coefficient of in (1) and in (2).

You need to write the terms the other way around:

The term in is now:

Now you can put and respectively.

Grandad

Ahh daym! no wonder I keep getting them wrong.. So its the other way around thank you Grandad :P

Originally Posted by Grandad

Hello jvignacioYour method is fine, but you have found the coefficient of in (1) and in (2).

You need to write the terms the other way around:

The term in is now:

Now you can put and respectively.

Grandad

Hey Grandad, how do we know how what coefficient to get from 1 and 2.. In this example.. , when you split the two brackets, you have to find the coeff of in the first bracket then find the coeff of in the second bracket.. but in the previous example it was from 1 and from 2.

thanks

EDIT: NEVERMIND, JUST GOT IT