Surd question (1 Viewer)

[XTsquared]

Hey guys, this is probably the wrong place to put this, as this is a 3u prelim question. But I'll give it a try anyway.

Having problems with one question:

Express with a rational denominator:

Again sorry if it is in the wrong spot. Thanks again.

 

[XTsquared]

Never mind, I got it! hahaha.

let 5^1/3 = a and let 2 = b

Cubic identity: a^3 + b^3 = (a+b)(a^2+ab+b^2)

1/(a+b) . (a^2+ab+b^2)/(a^2+ab+b^2)
= (a^2+ab+b^2)/a^3 + b^3

Sub in and voila.

Thanks anyway I spose.

 

[bleaver]

Hahah good work.

If all else fails:
(5^1/3+2)^-1 All over 1.
Maybe it'll get you a sympathy mark or something

 

[hscishard]

Never mind, I got it! hahaha.

let 5^1/3 = a and let 2 = b

Cubic identity: a^3 + b^3 = (a+b)(a^2+ab+b^2)

1/(a+b) . (a^2+ab+b^2)/(a^2+ab+b^2)
= (a^2+ab+b^2)/a^3 + b^3

Sub in and voila.

Thanks anyway I spose.

Its a^3 + b^3 = (a+b)(a^2- ab+b^2), careful lol