csat-suneung 2020 Q6

csat-suneung · South-Korea · csat__math-science 3 marks Standard trigonometric equations Solve trigonometric inequality

For $0 < x < 2 \pi$, what is the sum of all values of $x$ that simultaneously satisfy the equation $4 \cos ^ { 2 } x - 1 = 0$ and the inequality $\sin x \cos x < 0$? [3 points]
(1) $\frac { 10 } { 3 } \pi$
(2) $3 \pi$
(3) $\frac { 8 } { 3 } \pi$
(4) $\frac { 7 } { 3 } \pi$
(5) $2 \pi$

For $0 < x < 2 \pi$, what is the sum of all values of $x$ that simultaneously satisfy the equation $4 \cos ^ { 2 } x - 1 = 0$ and the inequality $\sin x \cos x < 0$? [3 points]\\
(1) $\frac { 10 } { 3 } \pi$\\
(2) $3 \pi$\\
(3) $\frac { 8 } { 3 } \pi$\\
(4) $\frac { 7 } { 3 } \pi$\\
(5) $2 \pi$

Paper Questions

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