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To find the coterminal angle of a given angle, we need to add or subtract 2\pi degree. If we have to find a negative coterminal angle, then in that case , we do subtraction but since here it is asked for a coterminal angle between 0 and 2 pi, so in this case we are searching for a positive coterminal angle and for that we have to add 2 \pi .
So the required coterminal angle is
-\frac{3 \pi}{10}+2 \pi = \frac{17 \pi}{10}
So the coterminal angle in 0 to 2\pi is \frac{17 \pi}{10} .
