Chain rule

There are 3 NRICH Mathematical resources connected to Chain rule
Exponential Trend
problem
Favourite

Exponential Trend

Age
16 to 18
Challenge level
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Find all the turning points of y=x^{1/x} for x>0 and decide whether each is a maximum or minimum. Give a sketch of the graph.
Quick Route
problem
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Quick Route

Age
16 to 18
Challenge level
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What is the quickest route across a ploughed field when your speed around the edge is greater?
What's my equation?
problem

What's my equation?

Age
16 to 18
Challenge level
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Can you find the differential equations giving rise to these famous solutions?