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Unlocking Calculus. Getting started on Integrals. The Integral. What is it? The area underneath a curve Why is it useful? It helps in Physics, Chemistry, Engineering Total energy of a system, total force, mass … It is one step closer to Truth!. Sir Isaac Newton (1642-1727).
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Unlocking Calculus Getting started on Integrals
The Integral • What is it? • The area underneath a curve • Why is it useful? • It helps in Physics, Chemistry, Engineering • Total energy of a system, total force, mass … • It is one step closer to Truth!
Sir Isaac Newton (1642-1727) Gottfried Wilhelm Leibnitz (1646-1716) Newton v. Leibnitz HistoryWho “invented” the integral? Calculus
Here’s what we write: Here’s what we mean: The area from a to b underneath the function f(x) with respect to x. Huh? Notation
What does it mean? The area from 2 to 4 underneath the function f(x)= x with respect to x So the area of the square is 4 and the triangle is 2. Thus the answer is 6. For Starters
Here’s the graph We want to find the areaunder the graph from 1 to 3 But since this is a curve,we don’t have an exact formula for the area… So we should just give up! Not yet… The Next Step
We can approximate by using rectangles. The more rectangles we use,the closer the approximation. In, fact if we used an infinitenumber of rectangles, evenlyspaced, it would be exact! But I can’t draw that manyrectangles And you can’t add that many either! Just get close!
Calculus to the rescue • Calculus has found certain formulae that help solve such problems • We’ll unlock two of these formulae right now. • The Power Rule • The Addition Rule
The Power Function • A power function is any function with x raised to some exponential power. These are just a few examples
Here’s the general form: _____________________ In words, the integral of (x to the n) from a to b with respect to x is (x to the n+1) over (n+1) evaluated from a to b, which is [(b to the n+1) over (n+1)] minus [(a to the n+1) over (n+1)]. The Power Rule
Example • Here’s one for starters
Few functions are simple power functions. Many involve addition of two or more simple power functions So, there’s a rule to handle such common functions. Addition of Functions
The general rule is written _______________ ________ ________ (in words) The integral from a to b of the function [g(x)+h(x)] with respect to xisthe integral from a to b of g(x) with respect to xplusthe integral from a to b of h(x) with respect to x. OR the integral of a sum is the sum of the integrals (and vice versa) Addition Rule
Example • Don’t forget the previous lessons, they’re important now!
There are many more kinds of functions, and thus many more integrating rules, but this is the intro. Click here to view a summary of related websites Remember, mastering the basics is the key to unlocking Calculus (and everything else) The “End”