Question

Prove the following:(a+b+c)^2=a^2+b^2+c^2+2(ab+bc+ca)​

Answer 1

Answer:

LHS=

$\\ (a + b + c) ^{2} \\ = ((a + b) + c) ^{2} \\ = (a + b) ^{2} + {c}^{2} + 2c(a + b) \\ = {a}^{2} + b ^{2} + 2ab + {c}^{2} + 2ac + 2bc \\ = {a}^{2} + {b}^{2} + {c}^{2} + 2(ab + bc + ca)$

=RHS