- #1
Woolyabyss
- 143
- 1
Homework Statement
Solve d^2x/dt^2 = (3x^3)/2
when dx/dt = -8 and x = 4 when t = 0
2. The attempt at a solution
v = dx/dt dv/dx = d^2/dx^2
d^2x/dt^2 = v(dv/dx) = (3x^3)/2
v dv = (3x^3)/2 dx
integrating and using limits and you get :
v^2/2 -32 = (3x^4)/8 - 96 ... 4v^2 = 3x^4 - 512
this is where I'm stuck I can take the square root of the 4v^2 but not the right hand side because of the three and the 512. I'm not sure if there is another technique I can use but finding the square root of both sides is the only way I was taught to do these problems and its the only example in the book.
Any help would be appreciated.