csat-suneung 2008 Q26

csat-suneung · South-Korea · csat__math-science 3 marks Addition & Double Angle Formulae Direct Double Angle Evaluation
(Calculus) When $\sin \alpha = \frac { 3 } { 4 }$, what is the value of $\cos 2 \alpha$? [3 points]
(1) $- \frac { 1 } { 32 }$
(2) $- \frac { 1 } { 16 }$
(3) $- \frac { 1 } { 8 }$
(4) $- \frac { 1 } { 4 }$
(5) $- \frac { 1 } { 2 }$
(Calculus) When $\sin \alpha = \frac { 3 } { 4 }$, what is the value of $\cos 2 \alpha$? [3 points]\\
(1) $- \frac { 1 } { 32 }$\\
(2) $- \frac { 1 } { 16 }$\\
(3) $- \frac { 1 } { 8 }$\\
(4) $- \frac { 1 } { 4 }$\\
(5) $- \frac { 1 } { 2 }$