What are the first three terms of the sequence: a1 = 3 and an = 2(an -1)^2?

a. 2, 8, 18

b. 3, 18, 648

c. 3, 32, 50

d. 2, 6, 12, 24

Question

What are the first three terms of the sequence: a1 = 3 and an = 2(an -1)^2?

a.        2, 8, 18

    b.    3, 18, 648

       c. 3, 32, 50

       d. 2, 6, 12, 24

parthkohli · Answer

First one would be 3. 2 options already eliminated.

anonymous · Answer

Yeah that's what I thought... I just don't know if the answer is b or c.... Can you please help me?

parthkohli · Answer

And then a2 would be 2(3)^2
= 2*9
= 18

parthkohli · Answer

Only one option is left now :D

anonymous · Answer

So b is the answer? and how'd you get that equation??

parthkohli · Answer

The equation is given in the question already

anonymous · Answer

@ParthKohli ARe you really good at math or something?

parthkohli · Answer

Yes I am :P

parthkohli · Answer

a2 = 2(a[2 - 1])^2
a2 = 2(a1)^2
a2 = 2(3)^2
a2 = 2 * 9
a2 = 18

That was easy lolol

anonymous · Answer

haha cool! If i need more help, can i just message you? haha what grade are you in?

parthkohli · Answer

I'm 12 years old...in 8th grade

anonymous · Answer

oh wow! so you're like really smart?

anonymous · Answer

what math are you in??

parthkohli · Answer

I guess..and that's what everyone says :P

parthkohli · Answer

I can help you with everything but trig or calculus

anonymous · Answer

awesome! Ima fan you... i might need more help in a bit hahaa :) thanks!

parthkohli · Answer

Hmm sure!