# math

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A 10 kg quantity of a radioactive isotope decays to 3 kg after 17 years. Find the decay constant of the isotope.

• math -

In en.wikipedia type: "Half-life"
and read text, and retype formulas.

So:

N(t)=N0*e^(-lambda*t)

N(t)=N(17)=3

N0=10

t=17

3=10*e^(-lambda*17) Divide with 10

3/10=e^(-lambda*17)

e^(-lambda*17)=3/10

-lambda*17=ln(3/10)Divide with 17

-lamba=ln(0.3)/17

lamda=-ln(0.3)/17

lamda=-(-1,203972804326)/17

lamda=1,203972804326/17

lamda=0,07082193

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