Solve the following equation:
-x^2+2x>0
To solve the inequality −x2+2x>0, we begin by considering the corresponding equation −x2+2x=0.
First, factor the quadratic equation:
- Rearrange the terms: −x2+2x=0 becomes x(2−x)=0.
- This gives us the roots x=0 and x=2.
These roots divide the number line into three intervals: x<0, 0<x<2, and x>2.
We need to test these intervals to determine where the inequality holds:
- For x<0, choose a test point like x=−1: the expression −(−1)2+2(−1)=−1−2=−3, which is not greater than zero.
- For 0<x<2, choose a test point like x=1: the expression −(1)2+2(1)=−1+2=1, which is greater than zero.
- For x>2, choose a test point like x=3: the expression −(3)2+2(3)=−9+6=−3, which is not greater than zero.
Thus, the inequality −x2+2x>0 is satisfied for the interval 0<x<2.
Therefore, the solution to the inequality is 0<x<2, which corresponds to choice 2 in the given options.