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I'm a little confused with how to use the output from DSolve. The following works

s = DSolve[{y'[x] == x, y[0] == 0}, y[x], x];
Plot[y[x] /. s, {x, 1, 10}]

but I don't understand how it works. I am familiar with /. a -> b which will replace a with b, but I don't get what y[x] /. s is doing?

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Dsolve[], like Solve[] (but unlike Resolve[]) returns replacement rules. You are replacing the value of y[]returned by your solve command

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  • $\begingroup$ Thanks. I see whats going on. I can declare a mapping such as map = {a->b}; then i can use this mapping variable in a any ReplaceAll command i.e a /. map or {a,a} /. map. $\endgroup$ – David McHarg Jan 26 '13 at 2:10
  • $\begingroup$ @David Yes. Replacement rules (term rewriting) are very important in Mathematica. $\endgroup$ – Dr. belisarius Jan 26 '13 at 9:25

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