solakis1
- 407
- 0
Solve the following equation
[$x^2+1$]=[2x] ,where [x] is the floor value of x
[$x^2+1$]=[2x] ,where [x] is the floor value of x
The equation $[x^2+1] = [2x]$ has solutions in the intervals $x \in [1/2, \sqrt{2}) \cup [3/2, \sqrt{3})$. The initial assumption that $x=1$ is the only solution is incorrect. The approach involves understanding the properties of the floor function, specifically that $x-1 \leq [x] < x$ and $2x-1 \leq [2x] < 2x$, leading to the conclusion that the upper and lower limits must be equal. This results in the quadratic equation $x^2 - 2x + 1 = 0$, which only identifies $x=1$ but does not encompass the full solution set.
PREREQUISITESStudents studying algebra, mathematicians interested in number theory, and educators looking for examples of floor functions in equations.
DaalChawal said:I'm getting only $x=1$ as the answer.
Here is my approach please do tell me If I'm wrong.
we know that $x-1 \le [x] \lt x$ so
$x^2 \le [x^2+1] \lt x^2 + 1 $ and
$2x-1 \le [2x] \lt 2x$
so the upper limits and lower limits must be equal
$x^2 - 2x + 1 = 0$ $\implies$ $x=1$
Where do you base that assumptionDaalChawal said:so the upper limits and lower limits must be equal