Addition and subtraction formulas Back … [Read more...]

## Trigonometric functions of any angle

Trigonometric functions of any angle Unit circle. Counting of angles in a unit circle. Negative and positive angles. Quarters of a unit circle. Sine and cosine lines. Sine. Cosine. Signs of sine and cosine in different quarters of a unit circle. Tangent and cotangent lines. Tangent. Cotangent. Signs of tangent and cotangent in different quarters of a unit circle. … [Read more...]

## Relations between trigonometric functions of the same angle

Relations between trigonometric functions of the same angle Main trigonometric identities. These formulas are the main trigonometric identities, that is to say, they are valid for any angle . Using them, it is possible to abridge and to simplify a calculation process. Back … [Read more...]

## Solving of right-angled triangles

Solving of right-angled triangles Solving of right-angled triangles: by two sides, by a side and an acute angle. 1. By two sides. If two sides of a right-angled triangle are given, then the third side can becalculated by the Pythagorean theorem ( see the paragraph of the same name in the section "Triangle" of the part "Geometry" ). Acute angles are … [Read more...]

## Trigonometric functions of an acute angle

Trigonometric functions of an acute angle Trigonometric functions of acute angle: sine, cosine, tangent, cotangent, secant, cosecant. Exact values of trigonometric functions for some most used acute angles. Trigonometric functions of an acute angle are ratios of different pairs of sides of a right-angled triangle ( Fig.2 ). 1) Sine: sin A = a / c ( a … [Read more...]

## Transforming of degree measure to radian one and back

Transforming of degree measure to radian one and back 1. To find a radian measure of any angle by its given degree measure it is necessary to multiply: a number of degrees by / 180 0.017453, a number of minutes – by / (180 · 60 )0.000291, a number of seconds – by / (180 · 60 · 60 ) 0.000005 and to … [Read more...]

## Radian and degree measures of angles

Radian and degree measures of angles Degree and radian measures of angles. Relation of a circle radius and a circumference length. Table of degree and radian measures for some most used angles. A degree measure. Here a unit of measurement is a degree (its designation is ° or deg ) – a turn of a ray by the 1 / 360 part of the one complete revolution. So, the … [Read more...]