# Solving differential equations by inspection and etc...

• Nov 7th 2012, 08:47 PM
tjsdndnjs
Solving differential equations by inspection and etc...
1. Solve the following DE’s, by inspection.
(a) y’= -sin x

2.Verify that the given function is a solution to the DE. Then determine c that satisfies the conditions given.
(a) xy’ = y ; y = cx; y=pie when x = 2

I have no clue how to start these 2 questions,,, Help please!

Thank you.
• Nov 7th 2012, 10:54 PM
a tutor
Re: Solving differential equations by inspection and etc...
a). You're lacking some basic knowledge. Before you start solving differential equations you should know among other things that if y=cos x then dy/ dx = -sin x.

b) Separate the variables.
• Nov 8th 2012, 05:23 AM
topsquark
Re: Solving differential equations by inspection and etc...
Quote:

Originally Posted by tjsdndnjs
(a) xy’ = y ; y = cx; y=pie when x = 2

You are about to be visited by Phil, the Prince of Insufficient Light and Ruler of Heck!!!

C'mon! You're in Calculus. It's spelled "pi" darn it all! (Angry)

-Dan