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#### karush

##### Well-known member

- Jan 31, 2012

- 2,928

$\textsf{find the solution:}$

$$y^\prime+(\tan x)y=\sin {2x} \quad -\pi < x < \pi/2$$

$\textit{find u(x)}$

$$u(x)=\exp\int \tan x \, dx = -e^{\ln(\cos x)}=-\cos x$$

ok just want to see if this first step is

$\tiny{\color{blue}{From \, Text \, Book: \,Elementary \, Differential \, Equations \, and \, Boundary \, Value \, Problems \,

by: \, William \, Boyce \, and \, Richard \, C. \, DiPrima \,

Rensselaer \, Polytechnic \, Institute, \, 1969}}$