trigonometric angle: Suppose
ray beam 0A 0B fixed and mobile. We begin with the two beams coincide. Now, we turn 0B about 0. In each position of rotation determines an angle 0B 0A: the angle A0B. It was agreed to consider the angles generated in a counter clockwise as positive as those generated in the same sense of clockwise and negative, according to the illustration on the right (Fig.1), the angle A0B is positive and the angle A0B 'is negative.
Before starting rotation, 0A and 0B rays coincide, forming an angle of 0 ° (sexagesimal). 0B Turning in the opposite direction clockwise, will generate an increasing angle and when you return to coincide with 0A 0B s
and will made a full turn, generating a rotation angle whose measure is 360 °. 0B may continue to rotate and generate an angle of any measure, of what follows that 0A and 0B are the initial and terminal sides, respectively, of an infinity of angles. unit of measurement of angles: the angles are expressed in degrees, grads or radians.
The sexagesimal system is considered to be the circumference divided into 360 equal parts, and an angle of 1 ° sexagesimal measure that is generated when the rotation in the same direction as the clockwise side of the terminal is of 1 / 360 part of a full turn. Each grade is considered to be divided into 60 equal parts called minutes and each minute into 60 equal parts called seconds. The symbols for these units are:
degrees ° minutes' seconds''
Radian: a radian is defined as the measure of a central angle subtended by an arc with the same length as the radius of the circunferncia . In (Fig.2), the radius r is equal to the arc AB, the angle A0B radians measured 1p.
In the circular system is used as the unit of measure the "radio."
In the system considered proximate to the circumference divided into 400 equal parts called "grads." Each grade has 100 minutes "grads" and every minute has 100 "seconds grads."
Equivalence of an angle in sexagesimal system to move and vice versa. To measure the angles, the most used systems are the sexagesimal and circular. It should know how to convert a given angle from one system to another.
position angle normal:
angle is said is in normal position when its initial side coincides with the positive semiaxis abscissas in a rectangular coordinate axes (Cartesian Plane). And whose apex is at the origin of coordinates (the point where the axes intersect).
In the right figure illustrates a normal position angle, the angle A0B.
Trigonometric Circle:
circle is called trigonometric, or goniometric to the circle whose center coincides with the origin of Cartesian coordinates and whose radius is unity.
On the right you can see a trigonometric circle.
