(a+h)^3

M

MRBoss429

New member
Joined
Feb 28, 2006
Messages
7
Pretty simple question, how do you expand (a+h)^3? Its for calculus but its just simple algebra. My algebra is really weak from a bad teacher experience which is making calc rough. Thanks for your help!!
 
\(\displaystyle \L
(x + h)^3 = x^3 + 3x^2 h + 3x h^2 + h^3\)
 
Or, if you don't remember the formula (provided above), just multiply it out:

. . . . .(a + h)<sup>3</sup> = (a + h)(a + h)(a + h)

Multiply.

Eliz.
 
Thanks guys, the problem I was having was multipying (a+h)(a+h)(a+h) out, I know how to do ^2 with foil, but I was sure how to go about doing ^3. Thanks again!
 
MRBoss429 said:
Thanks guys, the problem I was having was multipying (a+h)(a+h)(a+h) out, I know how to do ^2 with foil, but I was sure how to go about doing ^3. Thanks again!
Click to expand...
(a+h)(a+h) = a^2 + 2ah + h^2

(a+h)(a^2 + 2ah + h^2)

multiply (a^2 + 2ah + h^2) by a: a^3 + 2a^2h + ah^2
multiply (a^2 + 2ah + h^2) by h: a^2h + 2ah^2 + h^3

Now add 'em up; yes, it's that simple :idea:
 
Thanks a lot denis, I didnt even think to do it like that. Sometimes all it takes is for someone to literally spell it out for you!
 
(a+h)(a+h) = a^2 + 2ah + h^2

That's really done the same way:
multiply a by (a+h) : a^2 + ah
multiply h by (a+h) : ah + h^2
add 'em up.

So forget "FOIL"; it's only misleading!
 
MRBoss429 said:
Pretty simple question, how do you expand (a+h)^3? Its for calculus but its just simple algebra. My algebra is really weak from a bad teacher experience which is making calc rough. Thanks for your help!!
Click to expand...
Ah, my favorite argument against teaching calculus too soon. Really, if you can't cube a binomial, you have some serious catching up to do. Good luck. You'll need it.
 
You must log in or register to reply here.
Top