3. Two angles in standard position, having coincident terminal sides are called "coterminal angles."
   e.g. 30⁰, -330⁰ are coterminal angles.
   Note that with a given angle, there are unlimited number of coterminal angles.
   If x is an angle measured in degrees then its coterminal angles are given by, [coterminal angle of x = x⁰ + n (360⁰)], n being positive, negative or 0 integer.
   
   

Put       n = -2, -1, 0, 1, 2, 3.
when    n = -2, - 60⁰ + (-2) (360⁰) = - 780⁰
            n = -1, - 60⁰ + (-1) (360⁰) = - 420⁰
            n = 0, - 60⁰ + (0) (360⁰) = - 60⁰
            n = 1, - 60⁰ + (1) (360⁰) = - 300⁰
            n = 2, - 60⁰ + (2) (360⁰) = 660⁰
            n = 3, - 60⁰ + (3) (360⁰) = 1020⁰

       940⁰ = 200⁰ + n (360⁰ )
\    940⁰ - 200⁰ = n (360⁰ )
\    740⁰ = n (360)
\    n = which is not an integer.
\    The two angles are not coterminal.

4. If the terminal side of an angle coincides with one of the co-ordinate axes, then the angle is called as "Quadrantal angle."

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Index

2.1 Trigonometric Ratio of Acute Angles
2.2 Fundamental Relation between the trigonometric Ratios of an angle
2.3 Functions of General Angles or t Ratio
2.4 Tables of Trigonometric Function
Supplementary Problems

Chapter 3