[數學] 數學問題

From above, we can see this is a geometric sequence with a common ratio which is 4.

4 x 4 = 16
6 x 4 = 24

44 x 4 = 176
44 x 6 = 264

From the above examples, we can note that whenever 4 x 4, the last digit of the answer must be 6, while 6 x 4, the last digit of the answer must be 4.

For instance, if we expand the sequence, we can see 1,4,16,64,256,1024,,4096...
The last digits of the answers(apart from the first one), goes with 4, 6, 4, 6....
As we can see, for all the odd terms of the sequence (apart form the first one), all ends with 6.
Therefore, for the last digit of the 29th of the sequence is also 6.

1,4,16,64,256

這是4的n次方數列﹐由觀察可知當n是奇數時﹐個位數是6；當n是偶數時﹐個位數是4

而29是奇數﹐因此第29項的個位數是6