Question

(a+b)^3 - (a-b)^3=
Do it in detail

Answer 1

Hi friend
to solve
(a+b)^3 - (a-b)^3
first we solve
(a + b)3 = a^3 + 3a^2b + 3ab^2 + b^3
and secondly this
(a - b)3 = a^3 - 3a^2b + 3ab^2 - b^3
So
(a+b)^3 - (a-b)^3
=(a^3 + 3a^2b + 3ab^2 + b^3) - (a^3 - 3a^2b + 3ab^2 - b^3)
=a^3 + 3a^2b + 3ab^2 + b^3 - a^3 + 3a^2b - 3ab^2 + b^3
= 2(3a^2b) + 2(3ab^2) + 2(b^3). [a^3 will get cancelled]
=6a^2b + 6ab^2 + 2b^3

hope this is helpful