'Basic calculus' expert here doesn't know what a
real number is. Guess what, imaginary numbers aren't real numbers either. Wanna tell the electrical engineers and physicists that they don't apply to the real world?
What is your ignorant problem with basic calculus?
Are you better than Newton?
Real numbers have some correspondence to reality, thus the name. They abstractly represent real quantities.
But infinity is pure fantasy. There is not even the chance of a correspondence to reality.
And no physicist with a brain would think the infinity they use in their calculations actually corresponds to something real.