If yyou have the expand (1/2x + x/2)^3 should you first make the first bit of the bracket 1??
Because in another example it said you should make it (1+...). When would you have to do this??
- Thread Starter
- 13-03-2016 13:02
- Official Rep
- 15-03-2016 14:20
Sorry you've not had any responses about this.
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- 15-03-2016 22:32
No you don't because if you look at that other example you mentioned, the bracket is (1+/-....)^... to start off with (1+...)
Let's just say you had to expand (1+3x)^5 ok. You would start off with: 5C0 (1)^5 + 5C1 (1)^4(3x)^1 + 5C2 (1)^3(3x)^2..... OR 5C0 (1)^5 + 5C1 (3x) + 5C2 (3x)^2 + .....
This would be simplified to: 1 + 15x + 90x^2
However in your example of (1/2x + x/2)^3, you would start off with: 3C0 (1/2x)^3 + 3C1 (1/2x)^2(x/2) + .....
Now simplify this and you'd get 1/8x^3 as your first term. That's because the left number in the bracket (I don't know the name of it, sorry) is not 1.
If this is not clear, let me know, writing it on paper may be easier to understand.Last edited by ManLike007; 15-03-2016 at 22:34.