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# January 06 Modulus Question OCR watch

1. The function f is defined by f(x) = 2 - sqrt(x)
for X greater than or equal to 0

Given that | f(x) | = k has two distinct roots determine the possible values of the constant K.

I sketched the graph of | f(x) | and got

0=< k =<2

However they wanted
0< k =<2

Why is it 0<k and not 0=< k ?

Cheers.
2. If k=0, then f(x)=0, therefore sqrt(x)=2 is the only solution.
3. Try solving the equation for the case k=0. There is only one root.
4. Thanks both of you
Thinking about it now it should have been obvious to me, because the sketch of the graph produced a V shape, so at the bottom of the V there was only oen root.

Thanks

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