What is the pattern in the sequence, #28, -2, -32, -62#?

1 Answer
Jan 15, 2016

So 'the pattern' is: "Subtract 30 from the previous number"

Explanation:

The first thing to try is to see if this is an Arithmetic sequence.

Suppose we had:
#n_1=28color(white)(....)-> 1st" position"#
#n_2=-2color(white)(.)->2nd" position"#
#n_3=-32->3rd" position"#
#n_4=-62->4th" position"#

#n_2-n_1=-2-28=-30#
#n_3-n_2=-32-(-2)=-30#
#n_4-n_3=-62-(-32)=-30#

The consistent difference demonstrates that this is an Arithmetic Sequence

#color(magenta)("So 'the pattern' is: Subtract 30 from the previous number")#

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(blue)("Using algebra to represent this")#

So if #n_i# represents the value in position #i#:

#color(blue)(n_i=n_(i-1)-30)# where #n_(i-1)# represents the value in the previous position