Urgent help! Tomorrow is my exam!

Form the differential equation of the family of parabolas having vertex at the origin and axis along positive y-axis

Question

Urgent help! Tomorrow is my exam!

Form the differential equation of the family of parabolas having vertex at the origin and axis along positive y-axis

anonymous · Answer

@No.name @ganeshie8

anonymous · Answer

|dw:1405436088961:dw|

So I know the formula is x^2 = 4ay

ganeshie8 · Answer

thats a good start !

anonymous · Answer

So If I do y' I get 2x dy/dx= 4a

What do I do after this?

ganeshie8 · Answer

x^2 = 4ay

differentiating both sides with respect to x gives you

2x= 4a*dy/dx

ganeshie8 · Answer

solve the value of a from first equation and plugin above^^

ganeshie8 · Answer

x^2 = 4ay

a =  x^2/4y

ganeshie8 · Answer

so the differential equation becomes :

2x= 4(x^2/4y)*dy/dx

simplify

anonymous · Answer

I'm a bit confused and very nervous, I should probably avoid learning new concepts a few hours before exam.. right?