Exponential growth question (stalactites)

[Guest]

The growth of stalactites is given by S(t) = 210^kt where S is the length in metres and t is the time in years. After 1 year, a statalactite gains 1.2 cm in length. Calculate the amount of time in years for the crystal to double in length.

Is doubling time = log(2)/log(1 + percentage growth)/100)

Is there some information missing in the above question?

thank you in advance

 

[tkhunny]

Is there some information missing in the above question?

What is S(t)?

Is it length or growth or what?

If it is "length", note that S(0) = 210^(k*0) = 1?? What does that mean? One would need to solve something for 'k'. No such information has been given. Something missing? Yes.

If it is "growth", note that S(1) = 210^(k*1) = 1.2 cm = 0.012 m and you can solve for 'k'. k = -0.827147875. Something missing? Yes. We still don't know how to double anything, since we don't know how long it started. If S(t) had been defined as percentage growth, that might be diferent.

I think we need a new problem statement.

 

[Guest]

thank you

I thought that was the case...