A certain radioactive isotope has a half-life of 15 days. If one is to make a table showing the half-life decay of a sample of this isotope from 32 grams to 1 gram; list the time (in days, starting with t = 0) in the first column and the mass remaining (in grams) in the second column, which type of sequence is used in the first column and which type of sequence is used in the second column?

Question

***[isuru]*** · Answer

hi,
 the first column t is an arithmetic sequence... 
     'cause
             the day s will varies as
 1, 2, 3, 4, 5, ,6, .... so on until to 15
          I think ya can understand that one...

 the second column is a geometric sequence..
       'cause
                 if the weight is lose by 1/4 each day
  when 
               t = 1  the weight is 32 g
              t = 2 the weight will be 32x(1/4) = 8
              t = 3  the weight will be 8x(1/4) = 2

always the weight is multiplied by a common ratio  to find the next weight..
          so... that's a geometric progression

Did ya get it ?

anonymous · Answer

ahhh yes I do

***[isuru]*** · Answer

so...  i guess ya have no problems this time :-)