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\left. \begin{array} { l } { x \leq 2 \pi \text { is } } \\ { \frac { \pi } { 3 } } \\ { \frac { \pi } { 3 } , \frac { 5 \pi } { 3 } , \operatorname { cos } ^ { - 1 } ( - \frac { 3 } { 2 } ) ( \text { d } ) \text { } } \end{array} \right. |
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Answer» 6cosx - 3 + 4cos^2x - 2cosx = 04cos^2x + 4cosx - 3 = 0D = 16 + 48 = 64root D = 8cosx = (-4 + 8)/8 or (-4-8)/8= 1/2 or -3/2so, cosx = 1/2and x = 2npi +_ (pi/3) |
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