Power series solution of differential equations calculator

The calculator will try to find the solution of the given ODE: first-order, second-order, nth-order, separable, linear, exact, Bernoulli, homogeneous, or inhomogeneous.

Initial conditions are also supported.

Enter an equation (and, optionally, the initial conditions):

For example, y''(x)+25y(x)=0, y(0)=1, y'(0)=2.

Write `y'(x)` instead of `(dy)/(dx)`, `y''(x)` instead of `(d^2y)/(dx^2)`, etc.

If the calculator did not compute something or you have identified an error, or you have a suggestion/feedback, please write it in the comments below.

Solving linear differential equations with constant coefficients reduces to an algebraic problem. There is no similar procedure for solving linear differential equations with variable coefficients. With the exception of special types, such as the Cauchy equations, these will generally require the use of the power series techniques for a solution.

Application Details

Publish Date: May 23, 2007
Created In: Maple 11
Language: English

Power Series Calculator is a free online tool that displays the infinite series of the given function. BYJU’S online power series calculator tool makes the calculation faster, and it displays the expanded form of a given function in a fraction of seconds.

How to Use the Power Series Calculator?

The procedure to use the power series calculator is as follows:
Step 1: Enter the function, variable, point, order in the respective input field
Step 2: Now click the button “Calculate” to get the power series
Step 3: Finally, the power series of the given function will be displayed in the new window

What is Meant by Power Series?

In Mathematics, a power series is defined as an infinite series which is similar to the polynomial with many terms. Usually, the power series will converge at a value “x” within a certain interval, such that the absolute value of x is less than some positive value “r”, which is known as the radius of convergence.
The general form of the power series is given by:

\(\begin{array}{l}a_{0}+a_{1}x+a_{2}x^{2}+a_{3}x^{3}+…\end{array} \)

All ExamplesMathematics

Examples for

A differential equation is an equation involving a function and its derivatives. It can be referred to as an ordinary differential equation (ODE) or a partial differential equation (PDE) depending on whether or not partial derivatives are involved. Wolfram|Alpha can solve many problems under this important branch of mathematics, including solving ODEs, finding an ODE a function satisfies and solving an ODE using a slew of numerical methods.

Ordinary Differential Equations

Solve an ODE or find an ODE a function satisfies.

Solve a linear ordinary differential equation:

y'' + y = 0

w"(x)+w'(x)+w(x)=0

Specify initial values:

y'' + y = 0, y(0)=2, y'(0)=1

Solve an inhomogeneous equation:

y''(t) + y(t) = sin t

x^2 y''' - 2 y' = x

Solve an equation involving a parameter:

y'(t) = a t y(t)

Solve a nonlinear equation:

f'(t) = f(t)^2 + 1

y"(z) + sin(y(z)) = 0

Find differential equations satisfied by a given function:

differential equations sin 2x

differential equations J_2(x)

Numerical Differential Equation Solving

Numerically solve a differential equation using a variety of classical methods.

Solve an ODE using a specified numerical method:

Runge-Kutta method, dy/dx = -2xy, y(0) = 2, from 1 to 3, h = .25

{y'(x) = -2 y, y(0)=1} from 0 to 2 by implicit midpoint

Specify an adaptive method:

solve {y'(x) = -2 y, y(0)=1} from 0 to 10 using r k f algorithm

More examples

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Step-by-Step Solutions for Differential Equations

  • Applied Mathematics
  • Bessel & Related Functions
  • Calculus & Analysis
  • Elliptic Functions
  • Physics
  • $\begingroup$

    The equation is

    $$y'' - xy' + y = 0$$

    So far I have the recurrence relation -

    $$a_{n+2} = \dfrac{(n-1)a_n}{(n+1)(n+2)} $$

    From this -

    $a_2 = \dfrac{-a_0}{2!}$

    $a_3 = 0$

    $a_4 = \dfrac{-a_0}{4!}$

    $a_5 = 0$

    $a_6 = \dfrac{-3a_0}{6!}$

    and so on..

    The question asks for the first five non-zero terms of a general series solution of the d.e, seperating out for $a_0$ and $a_1$

    How do I compute this?

    Thanks

    asked Apr 27, 2014 at 21:49

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    11

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    The differential equation \begin{align} y^{''} - x y^{'} + y = 0 \end{align} can be solved via a power series of the form \begin{align} y(x) = \sum_{k=0}^{\infty} a_{n} x^{n} = a_{0} + a_{1} x + a_{2} x^{2} + \cdots . \end{align} It is fairly evident that \begin{align} \sum_{k=0}^{\infty} k(k-1) a_{k} x^{k} = \sum_{k=0}^{\infty} (k-1) a_{k} x^{k} \end{align} which yields the equation for the coefficients \begin{align} a_{k+2} = \frac{ (k-1) a_{k} }{ (k+1) (k+2) }. \end{align} It is discovered that $a_{3} = 0 \cdot a_{1}$. Since, for $k$ being odd, say $k \rightarrow 2k+1$, \begin{align} a_{2k+3} = \frac{k a_{2k+1} }{(k+1)(2k+3)} \end{align} it is clear that all the odd coefficients depend of $a_{3}$ for $k \geq 1$ and leads to $a_{2k+1} = 0$ for $k \geq 1$. The even $k$ values are \begin{align} a_{2} &= - \frac{a_{0}}{2!} \\ a_{4} &= - \frac{a_{0}}{4!} \\ a_{6} &= - \frac{(1 \cdot 3) a_{0}}{6!} \\ a_{8} &= - \frac{(1\cdot 3 \cdot 5)a_{0}}{8!} \end{align} which has the general form \begin{align} a_{2k} = - \frac{a_{0}}{2^{k} k! (2k-1)}. \end{align} The series for $y(x)$ now be seen in the form \begin{align} y(x) = a_{0} + a_{1} x - a_{0} \sum_{k=1}^{\infty} \frac{ x^{2n} }{2^{k} k! (2k-1)}. \end{align}

    The power series discovered can be evaluated as follows. Consider \begin{align} \partial_{x} \left( \sum_{k=1}^{\infty} \frac{ x^{2n-1} }{2^{k} k! (2k-1)} \right) &= \sum_{k=1}^{\infty} \frac{ x^{2n-2} }{2^{k} k!} = \frac{1}{x^{2}}( e^{x^{2}/2} -1). \end{align} Integrating both sides \begin{align} \sum_{k=1}^{\infty} \frac{ x^{2n} }{2^{k} k! (2k-1)} &= x \int^{x} \frac{e^{u^{2}/2} -1}{u^{2}} du = x \left[ \sqrt{\frac{\pi}{2} } erfi\left( \frac{x}{\sqrt{2}} \right) - \frac{e^{x^{2}/2}}{x} + \frac{1}{x} \right] \\ &= \sqrt{\frac{\pi}{2} } \cdot x \cdot erfi\left( \frac{x}{\sqrt{2}} \right) - e^{x^{2}/2} + 1. \end{align} With this series the general solution of $y(x)$ can be sen by \begin{align} y(x) &= a_{0} + a_{1} x - \sum_{k=1}^{\infty} \frac{ x^{2n} }{2^{k} k! (2k-1)} \\ &= a_{1} x - a_{0} \left[ \sqrt{\frac{\pi}{2} } \cdot x \cdot erfi\left( \frac{x}{\sqrt{2}} \right) - e^{x^{2}/2} \right], \end{align} where $erfi(x)$ is the imaginary error function (erfi(x) = -i erf(ix)).

    answered May 9, 2014 at 5:20

    LeucippusLeucippus

    22.9k145 gold badges39 silver badges84 bronze badges

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