Answer: Our Cost function is discontinuous at every integer after x>10.
Step-by-step explanation:
Since we have given that
For the first 10 minutes , the service charges = $0.30
Let the number of additional minute be 't'.
Amount charge for each additional minute = $0.05
Using the greatest integer function:
So, Cost C of a call in terms of time 't' minutes would be
![C=0.03+0.05\left \lceil t-10 \right \rceil](https://tex.z-dn.net/?f=C%3D0.03%2B0.05%5Cleft%20%5Clceil%20t-10%20%5Cright%20%5Crceil)
As we know that Greatest integer is discontinuous at every integer.
So, our Cost function is discontinuous at every integer after x>10.