Some binomial questions (2 Viewers)

[sadpwner]

How do you do these? There are no solutions in the textbook so idk if i am doing it right

 

[photastic]

How do you do these? There are no solutions in the textbook so idk if i am doing it right

7 (a) Simply equate the coefficients of x^r for both sides.
8 (a) If you inspect the expansion of (1+x)^n you realise the expansion is actually that sigma form when you let x=1
9 (a) Simply equate the coefficients of x^(n+r) for both sides.

 

[sadpwner]

7 (a) Simply equate the coefficients of x^r for both sides.
8 (a) If you inspect the expansion of (1+x)^n you realise the expansion is actually that sigma form when you let x=1
9 (a) Simply equate the coefficients of x^(n+r) for both sides.

I got the rest but I can't do 8. Can you show me steps for it. When you sub the things in it's true but I don't get how to show it.

 

[photastic]

I got the rest but I can't do 8. Can you show me steps for it. When you sub the things in it's true but I don't get how to show it.

 

[sadpwner]

Lol that was easier than expected. How do you do the next one?

 

[seanieg89]

Lol that was easier than expected. How do you do the next one?