Very short binomial question, help appreciated! :D

Hi

what does 'expand (1+6x)^2 for 5 non zero terms
What does that mean? :/
that isn't the real question, i've used it so as not to add my actual question, as it's not really that part of the question i need help with-if that makes sense.

Thanks

Reply 1

CallumCameron

It means the first 5 terms (constant, x, x^2 etc) that do not equal zero. The more terms you have, the closer it is to the original form.
The example you gave, (1+6x)^2, expands to 1+12x+36x^2 so I'm a little confused. You would usually have a non-natural number as your exponent for the question to make sense.

The green is very hard to read... :P

What board you with?

OP

Original post by CallumCameron

It means the first 5 terms (constant, x, x^2 etc) that do not equal zero. The more terms you have, the closer it is to the original form.
The example you gave, (1+6x)^2, expands to 1+12x+36x^2 so I'm a little confused. You would usually have a non-natural number as your exponent for the question to make sense.

The green is very hard to read... :P

Sorry about the green :tongue:

so, if my expansion part i have: 1 + 3/2ax + 3/8a^2x^2...., is that what they mean by non zero terms? and if it's '5 non zero terms' then it's upto x^6, right?

Thanks alot :smile:

Reply 4

CallumCameron

Original post by dream123

Sorry about the green :tongue:

so, if my expansion part i have: 1 + 3/2ax + 3/8a^2x^2...., is that what they mean by non zero terms? and if it's '5 non zero terms' then it's upto x^6, right?

Thanks alot :smile:

Yes, that's what they mean. Although it should be up to x^4 as the constant is also included. If you do come across a term that does equal zero, just add an extra term on the end so you still have 5. Eg, if x^3 had a coefficient that was zero, x^5 would be the fifth non-zero term.

Hope that helps! :smile:

(edited 13 years ago)

Reply 5

dream123

OP

2

Original post by CallumCameron

Yes, that's what they mean. Although it should be up to x^4 as the constant is also included. If you do come across a term that does equal zero, just add an extra term on the end so you still have 5. Eg, if x^3 had a coefficient that was zero, x^5 would be the fifth non-zero term.

Hope that helps! :smile: