First order differential equations

There are 2 NRICH Mathematical resources connected to First order differential equations
It's only a minus sign
problem

It's only a minus sign

Age
16 to 18
Challenge level
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Solve these differential equations to see how a minus sign can change the answer
Out in Space
problem

Out in Space

Age
16 to 18
Challenge level
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A space craft is ten thousand kilometres from the centre of the Earth moving away at 10 km per second. At what distance will it have half that speed?