Prove that if y= sinx/xy=sinxx, show that (d^2y)/(dx^2) + 2/x dy/dx + y = 0d2ydx2+2xdydx+y=0 ?

1 Answer
May 13, 2018

See below

Explanation:

If xy = sin xxy=sinx, using the product rule:

  • y + xy' = cos x qquad qquad qquad square

  • y' + y' + x y'' = - sin x qquad triangle

triangle/ x + square implies

(2y')/x + y'' + color( red)( y + xy') = - color(blue)((sin x)/x) + cos x

As color(blue)(y = (sin x)/x) and color(red)( y + xy' = cos x):

  • (2y')/x + y'' + cos x = - y + cos x

  • implies y'' + (2y')/x + y = 0