Question

What is the 20th term of the sequence that begins -4, 8, -16, 32

Answer 1

To find the 20th term of the sequence, we first need to determine the pattern in the sequence.

Looking at the terms of the sequence:

-4, 8, -16, 32

We can see that each term is double the previous term but alternating between positive and negative values.

Therefore, the pattern is: -4, 8, -16, 32, -64, 128, ...

Now, we need to find the 20th term in the sequence.

The 20th term is equal to (-4) * 2^(n-1) where n is the term number.

Substitute n=20 into the formula:

20th term = -4 * 2^(20-1)= -4 * 2^19 = -4 * 524288 = -2097152

Therefore, the 20th term of the sequence is -2,097,152.