1.

If and 0 < x < 2 π, then the solution areA. x = \(\frac{π}3\),\(\frac{4π}3\)B.  x = \(\frac{2π}3\),\(\frac{4π}3\)C.  x = \(\frac{2π}3\),\(\frac{7π}6\)D. x = \(\frac{2π}3\),\(\frac{5π}3\)

Answer»

We know if cos x = cos a 

Then 

x = 2nπ ± a 

here cos x = cos\((\frac{2π}3)\)

when n = 0, 

x = \(\frac{2π}3\)

when n = 1,

x = 2π - \(\frac{2π}3\) = \(\frac{4π}3\)

x =   \(\frac{2π}3\)\(\frac{4π}3\)

Option B



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