Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °
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There is also one more reason to check.
The concept of negative length I think already exists, but not in regular geometry.
I agree. You should always check any answers you get.
So answers may appear than are not solutions (unless you want to make a new topic in maths with 'negative lengths' )
Does that invalidate the quadratic formula, or completing the square or any other way to get roots? You are always required to check the roots! Also with combinatoric problems too...
I never said it di have to be easy. i am just saying that there should be another way of checking that doesn't require plugging in, because the solution may not be always pretty and a computer might not always be the when you need it.
You are missing the point.
-2 is a solution to the equation
It arises because of the method of solution.
Spurious solutions are detected by plugging in. -2 does not work.
I never said tachers new everything. It just seems logical. Even our book says it is better if we did itbthat way, so that we are sure both sides are positive.
I realise it will be hard for you to believe it but, sometimes, even teachers talk a load of rubbish.
Hi bob bundy!