√(4a²) = 2a?
In proving the quadratic formula I read this
(x + b/(2a))² = (b² - 4ac)/(4a²)
x + b/(2a) = (±√(b² - 4ac))/(2a)
Why did they do √(4a²) = 2a? Shouldn't it be 2|a|?
- Jeff AaronLv 76 months agoFavorite Answer
That doesn't matter because there's already a +/- in the numerator. So it works either way.
- llafferLv 76 months ago
You are correct it is technically:
But as Jeff stated, since you already have a ± in the numerator, adding one in the denominator doesn't change anything.