t
-------------------
________________
/ 2
\/ 1 - (w*t + f)
$$\frac{t}{\sqrt{- \left(t w + f\right)^{2} + 1}}$$
2
t *(f + t*w)
-------------------
3/2
/ 2\
\1 - (f + t*w) /
$$\frac{t^{2} \left(t w + f\right)}{\left(- \left(t w + f\right)^{2} + 1\right)^{\frac{3}{2}}}$$
/ 2 \
3 | 3*(f + t*w) |
t *|1 + --------------|
| 2|
\ 1 - (f + t*w) /
-----------------------
3/2
/ 2\
\1 - (f + t*w) /
$$\frac{t^{3} \cdot \left(\frac{3 \left(t w + f\right)^{2}}{- \left(t w + f\right)^{2} + 1} + 1\right)}{\left(- \left(t w + f\right)^{2} + 1\right)^{\frac{3}{2}}}$$