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Can somebody express this in terms of q,E,I,L,P.

d^2v / dx^2 = -(((P/L)*(l-x)^2)/2) / (E*I)

3 answers

looks like it already is, except for the q part.

I = dq/dt
oh yeah - I see an x hiding in there.

-(((P/L)*(l-x)^2)/2) / (E*I)
= -(PE/2IL)(1-x)^2

so, call all that junk k. Then you have

d^2/dx^2 = k(1-x)^2
dv/dx = -k/3 (1-x)^3 + c1
v = k/12 (1-x)^4 + c1*x + c2

Not sure what else you want to do with this.
I don't understand what you did ;>

I need v= .... but in answer I can use only q,E,I,L,P sa I have to remove x from this equation.