Suppose the drug atenolol is taken in 25 mg doses once a day to lower blood pressure. At the end of a 24 hour period, approximately 7 % of the atenolol is still present.

(a) Find expressions for the quantities
Q1, Q2, Q3, . . ., and Qn
, representing the amounts of atenolol in the body right after taking the 1st, 2nd, 3rd doses respectively. Then write the expression for
Qn
in closed-form.

Question

Suppose the drug atenolol is taken in 25 mg doses once a day to lower blood pressure. At the end of a 24 hour period, approximately 7 % of the atenolol is still present.

(a) Find expressions for the quantities
Q1, Q2, Q3, . . ., and Qn
, representing the amounts of atenolol in the body right after taking the 1st, 2nd, 3rd doses respectively. Then write the expression for
Qn
in closed-form.

anonymous · Answer

i think this is like summing a geometric sequence

anonymous · Answer

first term is 25
second term is $25+.07\times 25$

anonymous · Answer

does this look familiar?

anonymous · Answer

third term is 
$$25+.07(25+.07\times 25)=25+.07\times 25+.07^2\times 25$$

anonymous · Answer

and fourth , cutting to the chase, is 
$$25+.07\times 25+.07^2\times 25+.07^2\times 25$$ or 
$$25(1+.07+.07^2+.07^3)$$