SAT Math Practice Question #24611 - SATify | SATify

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SAT Math Practice Question #24611 - SATify | SATify

#24611

algebra

trigonometry

series

Calculus

hard

120 sec

If $\sum_{n = 0}^{\infty} (cos θ)^{n} = 3$ , what is the value of $cos 2 θ$ ?

A.

$\frac{1}{9}$

B.

$\frac{2}{9}$

C.

$- \frac{1}{9}$

D.

$- \frac{2}{9}$

E.

$\frac{4}{9}$