equation test

docs/system/motor_thrust_model.md

@@ -14,22 +14,12 @@ e.g. the model tells us that when we use 0.6 (60%) throttle, we will get 30N of
 
 The System uses a very simple but reliable model, which relies on the relationship between thrust and angular velocity of the propeller.
 The thrust is modelled as:
-When $a \ne 0$, there are two solutions to $(ax^2 + bx + c = 0)$ and they are 
-$$ x = {-b \pm \sqrt{b^2-4ac} \over 2a} $$
 
-% \f is defined as #1f(#2) using the macro
-\f\relax{x} = \int_{-\infty}^\infty
-    \f\hat\xi\,e^{2 \pi i \xi x}
-    \,d\xi
-
-
-
-    test
-
-
-
-
-For example:
+$$ T_d = a_t\sqrt{f_d} + b_t $$
+
+and:
+
+$$ x = {-b \pm \sqrt{b^2-4ac} \over 2a} $$
 
 $$
 \begin{aligned}