When you take calculus, you study situations which approach ∞/∞.
The expression, ∞/∞, is called "indeterminate" because the the problem that created it determines its value.
The value might be ∞, might be zero, might be 23.5, might be -12.75, etc.
So, without knowing the problem that created this situation, you don't really know what the answer should be, and it could be any number, or even ∞.