a) Find the coefficent of x in the expansion (2+x)^9
b)find the coefficent of x in the expansion (1-2x)^4(2+x)^9
not sure on how to do these questions could someone help please.
For a)
There is 1 term in binomial expansion with x. (2+x)9=(09)29⋅x0+(19)28x1+...
For b) Expanding it and multiplying out íou get x with coefficients in two case 1. In expansion of (1-2x)^4 x is on 0 power and in expansion of (2+x)^9 x is on 1 power (04)⋅19⋅(19)28⋅x
2. In exoansion of (1-2x)^4 x is on 1 power and in expansion of (2+x)^9 x is on 0 power (14)⋅(−2)x⋅(09)29
Calculate these term and add them together and you will get the coefficient.
hmmm im not sure how to do it without expanding the whole thing out, cause im pretty sure theres a method where you dont have to expand the whole thing
hmmm im not sure how to do it without expanding the whole thing out, cause im pretty sure theres a method where you dont have to expand the whole thing
I think you have been given plenty of clues, but If you can't see what to do, why don't you START the expansion?
The x term is near the beginning - so you won't have to expand the whole thing.