A tumor is injected with 0.5 grams of Iodine-125, which has a decay rate of 1.15% per day. Write an exponential model representing the amount of Iodine-125 remaining in the tumor after t days. Then use the formula to find the amount of Iodine-125 that would remain in the tumor after 60 days. Enter the exact answer. Enclose arguments of functions in parentheses and include a multiplication sign between terms. For example, c*exp(h) or c*ln(h).

m = 0.2508 g

Step-by-step explanation:

We know that for continuous exponential decay, we usually use the format;

N = N_o•e^(kt)

Where N and N_o represent amount after time t and intial amount respectively. And k is decay rate.

But in this case, we are dealing with mass.

Thus, we will use;

m = m_o•e^(-kt)

We are given;

Initial mass; m_o = 0.5 g

Time after decay; t = 60 days

Decay rate; k = 1.15% per day = 0.0115 per day

Thus;

m = 0.5e^(-0.0115 × 60)

m = 0.5 × 0.5016

m = 0.2508 g

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb