The distance from the origin (0,0) to the point Q(b,1) is:
\sqrt{b^2 + 1^2} = \sqrt{b^2 + 1}
The distance from Q to the point (1,3) is:
\sqrt{(b-1)^2 + (1-3)^2} = \sqrt{(b-1)^2 + 4}
Given that the distance from the origin to Q is half its distance to (1,3), we set up the equation:
\sqrt{b^2 + 1} = \frac{1}{2} \sqrt{(b-1)^2 + 4}
Square both sides to eliminate the square roots:
b^2 + 1 = \frac{1}{4} ((b-1)^2 + 4)
Multiply both sides by 4 to clear the fraction:
4(b^2 + 1) = (b-1)^2 + 4
Expand and simplify the equation:
4b^2 + 4 = b^2 - 2b + 1 + 4
4b^2 + 4 = b^2 - 2b + 5
4b^2 - b^2 + 4 + 2b = 5
3b^2 + 2b + 4 = 5
3b^2 + 2b - 1 = 0
Solve the quadratic equation using the quadratic formula:
b = \frac{-2 \pm \sqrt{2^2 - 4 \cdot 3 \cdot (-1)}}{2 \cdot 3}
b = \frac{-2 \pm \sqrt{4 + 12}}{6}
b = \frac{-2 \pm \sqrt{16}}{6}
b = \frac{-2 \pm 4}{6}
So, we have two solutions:
b = \frac{-2 + 4}{6} = \frac{2}{6} = \frac{1}{3}
b = \frac{-2 - 4}{6} = \frac{-6}{6} = -1
Therefore, the values of b can be:
\frac{1}{3} \text{ or } -1