70以上 a^3+b^3+c^3-3abc formula proof 261432-A^3+b^3+c^3-3abc formula proof
Show activity on this post We have a3 b3 c3 − 3abc = det (a b c c a b b c a) = (a b c)(a ωb ω2c)(a ω2b ωc) where ω = exp2πi 3 is a primitive third root of unity On the other hand a b c = ex, a ωb ω2c = eωx, a ω2b ωc = eω2x and 1 ω ω2 = 0, hence a3 b3 c3 − 3abc = e0x = 1Adding like terms, the final formula (worth remembering) is (a b c) 2 = a 2 b 2 c 2 2ab 2bc 2ac Practice Exercise for Algebra Module on Expansion of (a b c) 2What is formula of a3b3 Math Algebraic Expressions and Identities NCERT Solutions; A 3 B 3 C 3 3abc Formula A^3+b^3+c^3-3abc formula proof