I'm having second thoughts on the answers I came up with...

Einsteinium-235 decays at a rate of 3.406% per day.

a. find the annual decay rate in exact form:

100(.96594)^365

b. Compute an approximation of your solution in part a accurate to two decimal places:

(This is where I was thrown off, as my equation truncated to two decimal places comes out to be 0.00, and I'm sure that's not the intention.)

3.21 x 10^-4

c. Find the half-life of Einsteinium-235 in exact form:

100(.96594)^t=50

log(96.594^t)=log(50)

t x log(96.594)=log(50)

t=(log(50))/(log(96.594))

d. Compute an approximation of your solution in part c accurate to two decimal places

0.85

(But I know that's obviously wrong. )

Any help appreciated.