poison and math

Integral and differential.
King cobra poison extract from the scene Let's feel the math. Be very frightening.

Function F (x) by differentiating f (x) when it becomes, that is F '(x) = f (x) when the function F (x) and f (x) is called the indefinite integral.
F is right next to the poison in the prime symbol. Means that F is a differential. Because a small but powerful poison sir, you should not mistake.