Posts tagged integration
Inverse hyperbolic integrals

Inverse hyperbolic functions follow standard rules for integration. Remember, an inverse hyperbolic function can be written two ways. For example, inverse hyperbolic sine can be written as arcsinh or as sinh^(-1). Some people argue that the arcsinh form should be used because sinh^(-1) can be misinterpreted as 1/sinh. Whichever form you prefer, you see both, so you should be able to recognize both and understand that they mean the same thing.

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How to solve improper integrals

Improper integrals are just like definite integrals, except that the lower and/or upper limit of integration is infinite. Remember that a definite integral is an integral that we evaluate over a certain interval. An improper integral is just a definite integral where one end of the interval is +/-infinity.

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Finding a function's average value over a particular interval

Think about the average value of a function as the average height the function attains above the x-axis. If the function were y=3, then the height of the function is always 3 everywhere, so the average height of the function would also be 3. When the function gets more complicated, we can use the average value formula to find its average height on [a,b].

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How to solve initial value problems

We always lose the constant (term without a variable attached), when we take the derivative of a function. Which means we’re never going to get the constant back when we try to integrate our derivative. It’s lost forever. That is, unless we have an initial condition we can use to figure out what that constant was before we differentiated.

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Three methods for integrating quadratic functions

Quadratic functions are functions in the form ax^2+bx+c=0. Integrating functions that include a quadratic can sometimes be a little difficult. There are three methods we’ll use to evaluate quadratic integrals: substitution, partial fractions, and trigonometric substitution. You should try using these techniques in the order listed above, because substitution is the easiest and fastest, and trigonometric substitution is the longest and most difficult.

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Comparison theorem for improper integrals

The comparison theorem for improper integrals allows you to draw a conclusion about the convergence or divergence of an improper integral, without actually evaluating the integral itself. The trick is finding a comparison series that is either less than the original series and diverging, or greater than the original series and converging.

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How to find consumer and producer surplus

Consumer and producer surplus are values that a company can calculate to see when they have excess demand or production. If a company can better balance demand and production, they can be more profitable. We’ll need to calculate the equilibrium quantity and equilibrium price before we can find consumer surplus and producer surplus.

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Trapezoidal rule to estimate area under the curve

The trapezoidal rule is one method we can use to approximate the area under a function over a given interval. If it’s difficult to find area exactly using an integral, we can use trapezoidal rule instead to estimate the integral. It’s called trapezoidal rule because we use trapezoids to estimate the area under the curve.

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Surface area of revolution around the x-axis and y-axis

We can use integrals to find the surface area of the three-dimensional figure that’s created when we take a function and rotate it around an axis and over a certain interval. The formulas we use to find surface area of revolution are different depending on the form of the original function and the axis of rotation.

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U-substitution to solve definite integrals

U-substitution in definite integrals is just like substitution in indefinite integrals except that, since the variable is changed, the limits of integration must be changed as well. If you don’t change the limits of integration, then you’ll need to back-substitute for the original variable at the end.

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Theorem of Pappus to find volume using the centroid

The Theorem of Pappus tells us that the volume of a three-dimensional solid object that’s created by rotating a two-dimensional shape around an axis is given by V=Ad. V is the volume of the three-dimensional object, A is the area of the two-dimensional figure being revolved, and d is the distance traveled by the centroid of the two-dimensional figure.

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Probability density functions and probability of X in an interval

Probability density refers to the probability that a continuous random variable X will exist within a set of conditions. It follows that using the probability density equations will tell us the likelihood of an X existing in the interval [a,b].

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Work done on elastic springs, and Hooke's law

To find the work required to stretch or compress an elastic spring, you’ll need to use Hooke’s Law. Every spring has its own spring constant k, and this spring constant is used in the Hooke’s Law formula.

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