Graphing Shear and Moment using singuarity function in Excel

[mingyz0403]

Homework Statement

By Using singuarity function and Excel, plot shear and moment diagrams of the beam.

Relevant Equations

Shear and moment singuarity function

I had found the singuarity function for the shear and moment. I have a hard time calculating the singuarity function and graphing it using excel. Can anyone explain how to calculate singuarity function and graphing it using excel?

Many thanks for your help

 

[mingyz0403]

This is what I have done so far. Everything seems correct When X<6. When X>6, the calculation is wrong.The Shear force should be 30 kips. However, in Excel it was 48 kips.Could anyone tell what is wrong with my equation?

Many thanks for your help.