How do you know if a function is linear or quadratic?

Related questions

1. What is reference tracking?
2. What is slew motion?
3. What is set point tracking?
4. What is a feedback controller?
5. What does a transfer function do?
6. How do you use setpoint?
7. What is the difference between path and trajectory?
8. What is the meaning of tracking system?
9. What is trajectory tracking?
10. What is mathematical trajectory?

Tags

1. #functions
2. #parabolas
3. #slope
4. #typically
5. #graph
6. #point
7. #lines
8. #value
9. #start
10. #second
11. #straight
12. #intercept
13. #graphed
14. #quadratic
15. #linear
16. #curved