Page 15 - 10-Math-7 INTRODUCTION TO TRIGONOMETRY

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we use circular approach which involves
the unit circle. Let q. be a real number,
which represents the radian measure of
an angle in standard position. Let P (x, y)
be any point on the unit circle lying on
terminal side of q as shown in the figure.
We define sine of q, written as sin q
and cosine of q written as cos q as:

i.e, cos q and sin q are the x-coordinate and y-coordinate of the
point P on the unit circle. The equations x = cos q and y = sin q are
called circular or trigonometric functions.
The remaining trigonometric functions tangent, cotangent, secant
and cosecant will be denoted by tan q , cot q, sec q and cosec q for
any real angle q.

Reciprocal Identities Version 1.1

Example 2: Find the value of the trigonometric ratios at q
if point (3, 4) is on the terminal sides of q.

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