karjan07 wrote:
Bunuel wrote:
karjan07 wrote:
Bunuel,
When to use
1.\sqrt{x} = Mod(X) or
2. \sqrt{X} = X
Here u have used \sqrt{x} = Mod(X) while in the problem below:
If \sqrt{3-2x}= \sqrt{2x} +1 then 4x2 =
(A) 1
(B) 4
(C) 2 − 2x
(D) 4x − 2
(E) 6x − 1
you have used \sqrt{X} = X
Why so?
When to use
1.\sqrt{x} = Mod(X) or
2. \sqrt{X} = X
Here u have used \sqrt{x} = Mod(X) while in the problem below:
If \sqrt{3-2x}= \sqrt{2x} +1 then 4x2 =
(A) 1
(B) 4
(C) 2 − 2x
(D) 4x − 2
(E) 6x − 1
you have used \sqrt{X} = X
Why so?
\sqrt{x^2}=|x|.
If x\leq{0}. then \sqrt{x^2}=|x|=-x. For example if x=-5, then \sqrt{(-5)^2}=\sqrt{25}=5=|x|=-x.
If x\geq{0}, then \sqrt{x^2}=|x|=x. For example if x=5, then \sqrt{5^2}=\sqrt{25}=5=|x|=x.
I guess you are talking about the following problem: Where did I write that \sqrt{x^2}=x?
Got it... My mistake... was confused on \sqrt{(3x-2)}^2 = 3-2x
Probably should sleep now !!
Right.
In that question we have (\sqrt{3-2x})^2, which equals to 3-2x, the same way as (\sqrt{x})^2=x.
If it were \sqrt{(3-2x)^2}, then it would equal to |3-2x|, the same way as \sqrt{x^2}=|x|.
Check here: if-rot-3-2x-root-2x-1-then-4x-107925.html#p1223681
Hope it's clear.