Question

The definite integral is how obtain and the symbol of integral
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Answer 1

Symbol for definite integralThe ∫ symbol is called an integral sign; it's an elongated letter S, standing for sum. (The ∫ is actually the Σ from the Riemann sum, written in Roman letters instead of Greek letters.) The dx on the end must be included; you can think of∫ and dx as left and right parentheses.