The first term in a geometric sequence is 512 the fourth term is 1 find the first 4term

Mathematics

ScanSolve AI Answer

Answer

512, 64, 8, 1

Step-by-step solution

2 steps
  1. Determine the common ratio (rr)

    The formula for the nn-th term of a geometric sequence is an=a1⋅rn−1a_n = a_1 \cdot r^{n-1}.
    Given a1=512a_1 = 512 and a4=1a_4 = 1.

    a4=a1⋅r4−1a_4 = a_1 \cdot r^{4-1} 1=512⋅r31 = 512 \cdot r^3

    Divide both sides by 512:

    r3=1512r^3 = \frac{1}{512}

    Take the cube root of both sides:

    r=15123r = \sqrt[3]{\frac{1}{512}} r=18r = \frac{1}{8}
  2. Calculate the first 4 terms

    Using the common ratio r=18r = \frac{1}{8} and the first term a1=512a_1 = 512:

    a1=512a_1 = 512 a2=a1⋅r=512⋅18=64a_2 = a_1 \cdot r = 512 \cdot \frac{1}{8} = 64 a3=a2⋅r=64⋅18=8a_3 = a_2 \cdot r = 64 \cdot \frac{1}{8} = 8 a4=a3⋅r=8⋅18=1a_4 = a_3 \cdot r = 8 \cdot \frac{1}{8} = 1

    The first 4 terms of the geometric sequence are:

    512,64,8,1512, 64, 8, 1
Was this helpful?

Try one yourself

A new problem that tests the same skill.

Still stuck on this one?

Ask a follow-up, and the answer starts from this question.

Got a different question?Ask your own question