Porisma

A hint to get started

Build a fourth-degree series from a differential equation

The variables x and y are related by dy/dx=2xy−1dy/dx=2xy-1 and y=1 when x=0.

Show that, at x=0, d3y/dx3=−4d^3y/dx^3=-4 and d4y/dx4=12d^4y/dx^4=12.

Find the Maclaurin series for y up to and including the term in x4x^4, and hence find an approximation to the value of y when x=0.1, giving your answer to 5 decimal places.

CJC · Lecture · Example 6

Differentiate the relation before substituting zero, retain every product-rule contribution, and divide derivative values by the corresponding factorials.

Read the worked solution