- #1

Baggio

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I keep seeing this trick everywhere but I don't see how it is done.

how do we go from

[itex]\frac{1}{r^{2}}\frac{d}{dr}(r^{2}\frac{d \rho}{dr} [\latex]

to

[itex]\frac{1}{r} \frac{d^{2} \rhor}{dr^2{}}[\latex]

Ugggh can't get latex to work anyway it's

(1/r^2)(d/dr(r^2. dx/dr)

how do we go from that to

(1/r)(d/dr(r^2.d(xr)/dr))

I know for sure that they're equal I just don't know how to manipulate it! :(

Thanks

how do we go from

[itex]\frac{1}{r^{2}}\frac{d}{dr}(r^{2}\frac{d \rho}{dr} [\latex]

to

[itex]\frac{1}{r} \frac{d^{2} \rhor}{dr^2{}}[\latex]

Ugggh can't get latex to work anyway it's

(1/r^2)(d/dr(r^2. dx/dr)

how do we go from that to

(1/r)(d/dr(r^2.d(xr)/dr))

I know for sure that they're equal I just don't know how to manipulate it! :(

Thanks

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