what is the identity of this (a+b) cube
babitamor:
acube plus b cube plus 3asqb plus 3bsqa
not under
stand
Answers
Answered by
0
(a+b)^3=a^3+b^3+3ab (a+b)
Answered by
1
( a +b)^3 = a^3 + b^3 + 3ab (a +b)
_________________________
(a+b)^3 = (a+b) (a+b) (a+b)
= [ ( a^2 + ab + ab +b^2) (a +b)]
= [ ( a^2 + 2 ab +b^2) (a+b)]
= a^3 + 2a^2 b + ab^2 + a^2 b + 2ab^2 +b^3
= a^3 + b^3 + 3a^2 b + 3ab^2
= a^3 + b^3 + 3ab (a+b)
_________________________
(a+b)^3 = (a+b) (a+b) (a+b)
= [ ( a^2 + ab + ab +b^2) (a +b)]
= [ ( a^2 + 2 ab +b^2) (a+b)]
= a^3 + 2a^2 b + ab^2 + a^2 b + 2ab^2 +b^3
= a^3 + b^3 + 3a^2 b + 3ab^2
= a^3 + b^3 + 3ab (a+b)
Similar questions