Question

HOla gUyS...!!!! Pls koi mijhe..(a+b)^3 ka identity bata do...

Answer 1

Answer:

(a+b)^3= a^3+b^3+3a^2b+3ab^2

= a^3+b^3+3ab(a+b)

Answer 2

Let's find it ourselves!

(a + b)^3 can be written as,

(a + b) * (a + b) * (a + b)

Let's multiply the first two terms first.

[ (a +b) * (a + b) ] * (a + b)

[ a*a + a*b + b*a + b*b] * (a + b)

(a^2 + ab + ab + b^2) * (a + b)

(a^2 + 2ab + b^2) * (a + b)

Note :The term in the first parenthesis is the formula of (a + b) ^2 = (a + b) * (a + b)

Let's proceed further!

Let's multiply the the terms in two parentheses.

=> ( a^2 * a + a^2 * b +

2ab * a + 2ab * b +

b^2 * a + b^2 * b )

=> (a^3 + ba^2 + 2ba^2 + 2ab^2 + ab^2 + b^3)

=> (a^3 + 3ba^2 + 3ab^2 + b^3)

We can rewrite this formula much further. If you see, '3ab’ is common in 2nd and 3rd terms. So, let's take it out as common.

=>[a^3 + 3ab (a + b) + b^3]

Therefore, we can say,

(a + b)^3 = a^3 + 3ab (a + b) + b^3

Hope this helps!