Solve the Problem $2,1 , \frac { 1 } { 2 } , \frac { 1 } { 4 } , \ldots$

question 99

Multiple Choice

Solve the problem.
-For the geometric sequence $2,1 , \frac { 1 } { 2 } , \frac { 1 } { 4 } , \ldots$ , find $\mathrm { a } _ { \mathrm { n } }$ .

• A) \(a _ { n } = 2 ^ { 1 - n }\)
• B) \(a _ { n } = \left( \frac { 1 } { 2 } \right) ^ { 1 - n }\)
• C) \(a _ { n } = 2 ^ { n - 2 }\)
• D) \(a _ { n } = \left( \frac { 1 } { 2 } \right) ^ { n - 2 }\)

---

Definitions:

Direct Evidence

Evidence that directly proves a fact, without an inference or presumption, and which in itself, if true, conclusively establishes that fact.

Evolution

The method through which various types of life are believed to have evolved and branched out from ancestral forms throughout Earth's history.

Radioisotopes

Unstable isotopes that spontaneously emit radiation; also called radioactive isotopes.

Half-Life

The time required for half the atoms of a radioactive substance to decay or for a drug or other substance to lose half its pharmacologic, physiologic, or radiologic activity.