Here are the graphs corresponding to the given functions:

1. Function (a):

   • The waveform shows an increasing trend with noticeable jumps at specific points. The combination of the ramp and unit step functions creates a waveform that increases gradually and then has sudden changes at specific times (e.g., at $t = 1, 2, 3, 6$).

2. Function (b):

   • This is a sinusoidal function modulated by the unit step and ramp functions. The sine wave is active between specific intervals and cut off by step functions, which creates a waveform with discontinuities.

3. Function (c):

   • This waveform combines both ramp and unit step functions and has a mix of sharp jumps and linearly decreasing sections. The overall shape decreases, with multiple step changes at key points.

These plots represent the amplitude (in volts) versus time (in seconds) for the given functions.

Would you like more details on any specific part of these functions, or do you have any questions about their behavior?

Here are 5 questions that expand on the above content:

1. How does the ramp function $r(t)$ affect the overall shape of the waveform compared to the step function $u(t)$?
2. What impact does the sine term in function (b) have on the overall shape of the waveform?
3. Why do the waveforms in parts (a) and (c) have sharp jumps, and what causes them?
4. How would the graph change if the constants in front of each function were modified?
5. What role does time-shifting play in the appearance of these waveforms?

Tip: Always label key points (like where step functions activate) when sketching time-domain signals. This helps clearly understand their behavior.