Solving Exact Diff. Eqns w/ Coefficients >1 in Soln: dr/dΘ=(r^2 sin Θ)/(2r cos Θ -1)
I am trying to refresh my diffy and am having trouble recalling the handling of coefficents >1 in the solution. For example, given the exact differential equation:
dr/dΘ=(r^2 sin Θ)/(2r cos Θ -1)
Since it is exact I get the form Mdr + NdΘ = 0:
(2r cos Θ -1)dr-(r^2 sin Θ)dΘ = 0
Solving, I get:
2r^2 cos Θ -r = c
My book says the answer is:
r^2 cos Θ -r = c
I understand the concept of incorporating coefficients on the left into the constant on the right. However, in this case I don't see how the coefficient '2' can be incorporated from just the one term. How can a constant 'c' be obtained that does not change the relationship between the two terms? Can someone please explain? TIA.
I am trying to refresh my diffy and am having trouble recalling the handling of coefficents >1 in the solution. For example, given the exact differential equation:
dr/dΘ=(r^2 sin Θ)/(2r cos Θ -1)
Since it is exact I get the form Mdr + NdΘ = 0:
(2r cos Θ -1)dr-(r^2 sin Θ)dΘ = 0
Solving, I get:
2r^2 cos Θ -r = c
My book says the answer is:
r^2 cos Θ -r = c
I understand the concept of incorporating coefficients on the left into the constant on the right. However, in this case I don't see how the coefficient '2' can be incorporated from just the one term. How can a constant 'c' be obtained that does not change the relationship between the two terms? Can someone please explain? TIA.
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