## Sin, Cos and Tan

Summary First Quadrant: All are positive in this quadrant. Second Quadrant: Only sin is positive in this quadrant. Third Quadrant: Only tan is positive in this quadrant. Fourth Quadrant: Only cos is positive in this quadrant.   We now consider angles in cartesian plane. We divide the plane into four quadrants in the anticlockwise sense … Read more

## Sec, Cosec and Cot

Summary Secant (sec) is the reciprocal of cosine (cos): Cosecant (cosec) is the reciprocal of sin: Cotangent (cot) is the reciprocal of tan: Recall, in case of a right angle triangle if we are given one length and one angle and we have to find a missing length or if we need to find a … Read more

Summary 1 Revolution = 360° radian = 180° 1 radian = = 57.3° 1° =  radian  = 0.175 radian Length of arc  Area of a Sector   Area of a segment   The most common system of measuring the angles is that of degrees. One complete revolution is divided into 360 equal parts and each part is … Read more

## Sine and Cosine Rule

Summary Pythagoras theorem: only for right angle triangles:   For other triangles: 1.    Sine Rule: or 2.    Cosine Rule: or Area of a triangle :  Let’s quickly go back and recall the pythagoras theorem. We know that for any right angle triangle, if we have got lengths of two given sides, we can find the length … Read more

## Inequalities

Summary An inequality basically compares two statements with different values. An inequality is written with either a greater than sign ( >) or less than sign (< ). If we divide or multiply by a negative number, the direction of the inequality is changed. To solve a quadratic inequality we need to carry out the … Read more

## Set Theory

Summary The modern study of set theory was initiated by Georg Cantor and Richard Dedekind in the 1870s. A set is a collection of distinct objects, called elements of the set. Set’s are denoted by upper case letters and they are enclosed in curly brackets  {….}. When we write , this means x belongs to … Read more