2nd derivative problem

[Guest]

Hi guys,

How can I derivate the problem given in attachment

Thx

[HallsofIvy]

I hate having to tilt my head sideways! And wouldn't have been easier to type the question instead of taking a picture and downloading it?

The problem is, apparently, that you are given that [tex]\frac{d\theta}{d\eta}= \frac{k}{S_0R}\frac{dT}{dr}[/tex] and you want to determine [tex]\frac{d^2\theta}{d\eta^2}[/tex].
Okay, differentiate, with respect to [tex]\eta[/tex], again: [tex]\frac{d^2\theta}{d\eta^2}=[/tex][tex]\frac{d}{d\eta}\left(\frac{k}{S_0R}\frac{dT}{dr}\right)[/tex][tex]= \frac{k}{S_0R}\frac{d}{d\eta}\left(\frac{dT}{dr}\right)[/tex]

To go further than that, to determine [tex]\frac{d}{d\eta}\left(\frac{dT}{dr}\right)[/tex], there simply isn't enough information! What relation are T and r to [tex]\theta[/tex] and [tex]\eta[/tex]?