005 Sample Final A, Question 15

Question Find an equivalent algebraic expression for the following,

$\cos(\tan ^{-1}(x))$

Final Answers
a) False. Nothing in the definition of a geometric sequence requires the common ratio to be always positive. For example, $a_{n}=(-a)^{n}$
b) False. Linear systems only have a solution if the lines intersect. So y = x and y = x + 1 will never intersect because they are parallel.
c) False. $y=x^{2}$ does not have an inverse.
d) True. $cos^{2}(x)-cos(x)=0$ has multiple solutions.
e) True.
f) False.