Farm Power

For perfect steering without tire scrubbing according to Ackermann steering geometry, a tractor has a wheelbase $L = 2.1\text{ m}$ and front wheel track width $b = 1.4\text{ m}$. If the inner steer wheel angle is $\theta = 35^\circ$ ($\cot(35^\circ) = 1.428$), the required cotangent of the outer steer angle $(\cot \phi)$ is: