When will differentiation and integration be used in real life?

An engineer has to be able to do those things in his head while he is talking. You know those big blueprint pictures? A draftsman has to imagine the entire picture so he can start drawing in the right place and not run off the edge of the paper. Did you ever look at a spec sheet for an ic? An electronic engineer usually memorizes the entire sheet for every device he works with. Did you ever look at the music for a symphony? The director memorizes every note for every instrument. Amnesiacs do not do great things.

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