Note that √(x^2) is not the same as ∜x In any case, solving √(x^2) = 4 gives two answers: x = ±4 But solving √(x^2) = −4 gives no answer. Solving √(expression_1) = expression_2 only has solution when expression_2 ≥ 0 Same logic is used for fourth roots. At 9:30, expression_2 = (−1−√5)/2 < 0, so there is no solution
Yes indeed
9:30 ...hmm... sqr(x^2) = |x| = ±x
Note that √(x^2) is not the same as ∜x
In any case, solving √(x^2) = 4 gives two answers: x = ±4
But solving √(x^2) = −4 gives no answer.
Solving √(expression_1) = expression_2 only has solution when expression_2 ≥ 0
Same logic is used for fourth roots.
At 9:30, expression_2 = (−1−√5)/2 < 0, so there is no solution