Question

For a particular sequence, T1 = 3and Tn = -2Tn-1 +1 then T5 equals?

A: 7
B: 21
C: 11
D: 43

Answer 1

@Chlorophyll Think you could help?

Answer 2

Replace n = 5, can you?

Answer 3

I have no idea.

Answer 4

I'll rewrite the question so it looks clearer.

Answer 5

Is it Tn-1 has both the subscript n-1?

Answer 6

For a particular sequence, \[T _{1} = 3\] and \[T _{n} = -2t _{n-1}\] + 1, then \[T _{5}\] equals:

Answer 7

It's just like that x_X

Answer 8

I can't think of the shortcut !!!
Here's the simple way:
T2 = -2T1 +1 = -2 * 3 + 1 = -5
T3 = -2T2 +1 = -2 *(-5) +1 = 11
T4 = -2T3 +1 = -2 * 11+1 = -21
T5 = -2T4 +1 = -2*(-21)+1 = 42