Transpose Formula & Find Correct Solution: Homework Help

[j.will]

Homework Statement

I need to transpose the following equation to make E the subject (see deflection due to bending attachment .jpg) and I'm not sure whether my attempt is correct or not.
Could anybody advise on the corrections needed on my attempts.

Homework Equations

see deflection due to bending attachment

The Attempt at a Solution

See attempt 1 and attempt 2 attachments (.jpg)

 

[SteamKing]

Homework Statement

I need to transpose the following equation to make E the subject (see deflection due to bending attachment .jpg) and I'm not sure whether my attempt is correct or not.
Could anybody advise on the corrections needed on my attempts.

Homework Equations

see deflection due to bending attachment

The Attempt at a Solution

See attempt 1 and attempt 2 attachments (.jpg)

Your first attempt is completely incorrect. If you want to multiply both sides of the equation by 48EI, you must multiply ALL the terms on both sides by that amount, not just the ones which are convenient, where 48EI cancels out.

Your second attempt looks long winded, and I don't want to get caught in that Briar Patch.

The thing you have overlooked in both attempts is that E is a common factor in both terms of the RHS of the original equation. If you want to isolate E, then multiply both sides of the equation by E and divide both sides by δ. You must do this to ALL terms.