Power Series Methods
http://www.maa.org/taxonomy/term/41679/0
enPower Series Expansions for Trigonometric Functions via Solutions to Initial Value Problems
http://www.maa.org/programs/faculty-and-departments/classroom-capsules-and-notes/power-series-expansions-for-trigonometric-functions-via-solutions-to-initial-value-problems
<div class="field field-name-body field-type-text-with-summary field-label-hidden"><div class="field-items"><div class="field-item even"><p><em>Using initial value problem with repeated differentiations, the author obtains the complicated coefficients of the power series for powers of the secant function.</em></p>
</div></div></div>MIT OpenCourseware: 18.03 Differential Equations
http://www.maa.org/programs/faculty-and-departments/course-communities/mit-opencourseware-1803-differential-equations
Series Solutions
http://www.maa.org/programs/faculty-and-departments/course-communities/series-solutions
Series Solutions
http://www.maa.org/programs/faculty-and-departments/course-communities/series-solutions-0
Series Solution of a Cauchy-Euler equation
http://www.maa.org/programs/faculty-and-departments/course-communities/series-solution-of-a-cauchy-euler-equation
Series (Classroom Capsules and Notes)
http://www.maa.org/programs/faculty-and-departments/course-communities/series-classroom-capsules-and-notes