Let’s see the angles in different Quadrants

  • In Quadrant 1 , angles are from 0 to 90°
  • In Quadrant 2 , angles are from 90 to 180°
  • In Quadrant 3 , angles are from 180° to 270°
  • In Quadrant 4 , angles are from 270 to 360°

Angles in different quadrants.jpg

 

To learn sign of sin, cos, tan in different quadrants,

we remember

A dd → S ugar → T o → C offee

 

sin cos  tan in different quadrants.jpg

 

Representing as a table

 

Quadrant I

Quadrant II

Quadrant III

Quadrant IV

sin

+

+

cos

+

tan

+

+

 

What about cot, sec, cosec?

We know that

tan = sin/cos

sec = 1/cos

cosec = 1/sin

cot = 1/tan

 

So,

  • In 1 st quadrant -
    sin, cos both +ve.

    tan = sin/cos = +/+ = +
    cosec = 1/sin = 1/+ = +
    sec = 1/cos = 1/+ = +
    cot = 1/tan = 1/+ = +

  • In 2 nd quadrant -
    sin is +ve, cos is –ve.

    tan = sin/cos = +/– = –
    cosec = 1/sin = 1/+ = +
    sec = 1/cos = 1/– = –
    cot = 1/tan = 1/– = –

  • In 3 rd quadrant -
    sin is –ve, cos is –ve.

    tan = sin/cos = –/– = +
    cosec = 1/sin = 1/– = –
    sec = 1/cos = 1/– = -
    cot = 1/tan = 1/+ = +

  • In 4 th quadrant -
    sin is –ve, cos is +ve.

    tan = sin/cos = –/+ = –
    cosec = 1/sin = 1/– = –
    sec = 1/cos = 1/+ = +
    cot = 1/tan = 1/– = –
  1. Chapter 3 Class 11 Trigonometric Functions
  2. Concept wise
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Transcript

Let’s see the angles in different Quadrants In Quadrant 1, angles are from 0 to 90° In Quadrant 2, angles are from 90 to 180° In Quadrant 3, angles are from 180° to 270° In Quadrant 4, angles are from 270 to 360° To learn sign of sin, cos, tan in different quadrants, we remember Add → Sugar → To → Coffee Representing as a table Quadrant I Quadrant II Quadrant III Quadrant IV sin + + – – cos + – – – tan + – + – What about cot, sec, cosec? We know that tan = sin/cos sec = 1/cos cosec = 1/sin cot = 1/tan So, In 1st quadrant - sin, cos both +ve. tan = sin/cos = +/+ = + cosec = 1/sin = 1/+ = + sec = 1/cos = 1/+ = + cot = 1/tan = 1/+ = + In 2nd quadrant - sin is +ve, cos is –ve. tan = sin/cos = +/– = – cosec = 1/sin = 1/+ = + sec = 1/cos = 1/– = – cot = 1/tan = 1/– = – In 3rd quadrant - sin is –ve, cos is –ve. tan = sin/cos = –/– = + cosec = 1/sin = 1/– = – sec = 1/cos = 1/– = - cot = 1/tan = 1/+ = + In 4th quadrant - sin is –ve, cos is +ve. tan = sin/cos = –/+ = – cosec = 1/sin = 1/– = – sec = 1/cos = 1/+ = + cot = 1/tan = 1/– = –

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Davneet Singh
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