See the original problem statement. Why does Chegg's answer not include the given parameters of L and alpha as depicted in the diagram? L and alpha determine the change in gravitational potential energy between the top of the water in the tank and the pipe outlet $($i$.$e$.,$ H $-$ Lsin$($alpha$)),$ which should affect the calculation of the velocity of the water leaving the pipe, as well as the angle at which water leaves the pipe $($alpha$),$ which will affect the maximum height of the water when the valve is initially opened. Of course, Lsin$($alpha$)$ is not included when calculating the maximum height of the water stream because the pipe outlet is a ground level.