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River crossing - solve the problem

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Posljednje ažuriranje over 5 years ago
8
1

Using the formula for time taken for travel at a constant speed,

write down and expressionin terms of x for:

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1
1

You want to minimise this expression (find the minimum time taken).

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Pitanje 1
1.

What is the length of AC in terms of x?

Pitanje 2
2.

  • the time taken to swim from A to C.

Pitanje 3
3.

  • the time taken to run from C to D.

Pitanje 4
4.

Hence write down an expression for the time taken, T, to travel from A to D in terms of x.

Pitanje 5
5.

Find

Pitanje 6
6.

Now solve

to determine the value of x that minimises the time taken.

Pitanje 7
7.

How do you know this is a valid value?

Pitanje 8
8.

For this value of x, find the minimum time possible and descibe the route.