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Question

Question: How do you integrate \(\int{\dfrac{1}{{{x}^{3}}}dx}\)?...

How do you integrate 1x3dx\int{\dfrac{1}{{{x}^{3}}}dx}?

Explanation

Solution

We first explain the term dydx\dfrac{dy}{dx} where y=f(x)y=f\left( x \right). We then need to integrate the equation1x3dx\int{\dfrac{1}{{{x}^{3}}}dx} once to find all the solutions of the differential equation. We take one constant for the integration and use the formula of xndx=xn+1n+1+c\int{{{x}^{n}}dx}=\dfrac{{{x}^{n+1}}}{n+1}+c.

Complete answer:
We have to find the integral of the equation 1x3\dfrac{1}{{{x}^{3}}}. The mathematical form is 1x3dx\int{\dfrac{1}{{{x}^{3}}}dx}.
The main function is y=f(x)y=f\left( x \right). We can convert using index form as 1x3=x3\dfrac{1}{{{x}^{3}}}={{x}^{-3}}
So, 1x3dx=x3dx\int{\dfrac{1}{{{x}^{3}}}dx}=\int{{{x}^{-3}}dx}
We know the integral form of xndx=xn+1n+1+c\int{{{x}^{n}}dx}=\dfrac{{{x}^{n+1}}}{n+1}+c. We put the value of n=3n=-3.
Constant terms get separated from the integral.
Simplifying the integral form, we get 1x3dx=x3dx=x3+13+1+c=x22+c\int{\dfrac{1}{{{x}^{3}}}dx}=\int{{{x}^{-3}}dx}=\dfrac{{{x}^{-3+1}}}{-3+1}+c=\dfrac{{{x}^{-2}}}{-2}+c.
Here cc is another constant. The simplified form is 1x3dx=12x2+c\int{\dfrac{1}{{{x}^{3}}}dx}=-\dfrac{1}{2{{x}^{2}}}+c

Note:
The solution of the power equation integral is the equation of a power function. The formula is valid for all nn except 1-1. The first order differentiation of 12x2+c-\dfrac{1}{2{{x}^{2}}}+c gives the tangent of the circle for a certain point which is equal to dydx=1x3\dfrac{dy}{dx}=\dfrac{1}{{{x}^{3}}}.