karush
Gold Member
MHB
- 3,240
- 5
1183
well by completing the square from $x^2+3x$ we get $\pmatrix {x+\frac{3}{2}}^2 -\frac{9}{4}$
which means the vertex is more than $2$ below the x-axis but above at $3$
so from the set k only at $k=1$ and $k=2$ will it cross the x-axis so $\frac{2}{7}$ is the probability that the function will cross the x-axis.
one way i guess
well by completing the square from $x^2+3x$ we get $\pmatrix {x+\frac{3}{2}}^2 -\frac{9}{4}$
which means the vertex is more than $2$ below the x-axis but above at $3$
so from the set k only at $k=1$ and $k=2$ will it cross the x-axis so $\frac{2}{7}$ is the probability that the function will cross the x-axis.
one way i guess
Last edited: