[tex]\\ \sf\longmapsto C(t)=(t,\dfrac{t^2}{2})[/tex]
[tex]\\ \sf\longmapsto C(1/2)=,\dfrac{1}{2},\dfrac{(1/2)^2}{2})[/tex]
[tex]\\ \sf\longmapsto C(1/2)=(\dfrac{1}{2},\dfrac{\dfrac{1}{4}}{2})[/tex]
[tex]\\ \sf\longmapsto C(1/2)=(\dfrac{1}{2},\dfrac{1}{8})[/tex]
Now
Slope
[tex]\\ \sf\longmapsto \dfrac{y_2-y_1}{x_2-x_1}[/tex]
[tex]\\ \sf\longmapsto \dfrac{0-\dfrac{1}{8}}{0-\dfrac{1}{2}}[/tex]
[tex]\\ \sf\longmapsto \dfrac{\dfrac{1}{8}}{\dfrac{1}{2}}[/tex]
[tex]\\ \sf\longmapsto \dfrac{1}{4}[/tex]