turkey-yks 2011 Q28

turkey-yks · Other · lys1-math Addition & Double Angle Formulae Direct Double Angle Evaluation
$\cos \mathrm { x } = \frac { - 4 } { 5 }$ Given this, what is $\cos 2 \mathrm { x }$?
A) $\frac { 3 } { 5 }$
B) $\frac { 5 } { 13 }$
C) $\frac { 12 } { 13 }$
D) $\frac { 24 } { 25 }$
E) $\frac { 7 } { 25 }$
$\cos \mathrm { x } = \frac { - 4 } { 5 }$\\
Given this, what is $\cos 2 \mathrm { x }$?\\
A) $\frac { 3 } { 5 }$\\
B) $\frac { 5 } { 13 }$\\
C) $\frac { 12 } { 13 }$\\
D) $\frac { 24 } { 25 }$\\
E) $\frac { 7 } { 25 }$