Limits
If f(x)=(x^2+2) x<1, and f(x) = 4 for x > 1, is continuous at x=1?
No it is not continuous at x=1 because as x approaches 1 from the left the limit is 3 and from the right the limit is 4.
Is f(x)=x^2 where f(2) = 5, is f(x) continuous at x=2?
No this is a removable discontinuity at x=2.