OpenStudy (saylilbaby):

the 5th term in a geometric succession is 140. The 7th term is 35. What space the feasible values the the sixth term that the sequence?what is the 20th ax of the succession that starts -2,4,-8,16..?what is the 50th term of the sequence that starts -2,4,10,16....

You are watching: The 5th term in a geometric sequence is 140

5 years ago
OpenStudy (saylilbaby):

It is geometric progression so it have to be prefer thisFirst term =aSecond term=arThird termterm=ar^2...5th term=ar^4=140..7th term=ar^6=35Solve over two equation and find a,r

5 year ago

Can you fix for a and r.

5 years ago
zepdrix (zepdrix):

Geometric method you"re `multiplying` by part `common ratio` to get from one term come the next.So to acquire from ax 5 come term 6, you main point by r.(large m a_5=140)(large m a_6=140r)a_6 is simply the vault term multiply by this r value.Then to acquire from term 6 come term 7, you main point by r again,(large m a_7=140rcdot r)(large m a_7=140r^2)And then told united state the value of a_7, so let"s plug the in,Solve because that r! :)

5 years ago
zepdrix (zepdrix):

And then your 6th term is just 140 time the r.Solve because that r :U carry out ittttt

5 year ago
OpenStudy (saylilbaby):

i gained +-70
zepdrix (zepdrix):

70 for the middle term, a_6?

5 years ago
zepdrix (zepdrix):

Ooo pretty job! :)

5 year ago
zepdrix (zepdrix):

Ya good with the plus/minus.I assumption: v we could have our sequence be alternating.

5 year ago
zepdrix (zepdrix):

(large m -2,4,-8,16,...)Looks choose geometric again :)What room we multiply by every time?Find that r value! :o

5 year ago
zepdrix (zepdrix):

Good.And how do you gain from the 1st to the 20th term?I guess: v you would certainly multiply the an initial term by r ... 19 times!(One less because we didn"t use r to acquire our an initial term a_1)Or if you prefer, you can just skinny on her formula the they teach you,

5 year ago
zepdrix (zepdrix):

(large m -2,4,10,16....)The last one to be pretty obvious, we were doubling every time,so it to be multiplication by 2.How bout this one?Geometric or Arithmetic?Multiplying or including something each term?

5 years ago  