Binomial Problems (1 Viewer)

[Sarah182]

I can't do this topic :S

I havent had a chance to ask my teacher and my textbook doesnt have examples for these questions:

1. Find the constant term of:
(x-y)^6

2. Find the constant term of:
(3x+ (2/x^2)^9

could someone explain to me how to do this?

Thanking you all in advance

 

[Zeber]

1. Find the constant term of:
(x-y)^6

There is no constant term here. So 0 ?

2. Find the constant term of:
(3x+ (2/x^2)^9

(3x+ (2/x^2)^9
k = 12->0 ∑ 12Ck (3x)^k*(2x)^-2(12-k)

x^0 for a constant term.

x^k.x^(-2(12-k) = x^0, equating powers.
k-24+2k = 0
3k = 24
k = 8

Plugging k = 8 into
12Ck (3x)^k*(2x)^-2(12-k)

we get the constant to be 12C8.(3^8).(2^4)

 

[tacogym27101990]

I can't do this topic :S

I havent had a chance to ask my teacher and my textbook doesnt have examples for these questions:

1. Find the constant term of:
(x-y)^6

2. Find the constant term of:
(3x+ (2/x^2)^9

could someone explain to me how to do this?

Thanking you all in advance

how is this an exam thought of mathematics you goose