Question

if a square + b square + c square equal to 1 so that a b + BC + CA greater than or equal to minus 1by 2​

Answer 1

main formula

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

• (a+b+c)² is always greater than or equal to 0.

step by step explanation:

• (a+b+c)² ≥ 0
• a² + b² + c² + 2(ab+bc+ca) ≥ 0
• 1 + 2(ab + bc + ca) ≥ 0.

[given; a²+b²+c²=1]

• 2(ab + bc + ca) ≥ -1
• ab + bc + ca ≥ -1/2

amazing question!