EXERCISE 8.4

NCERT Solutions for Class 10 Maths Chapter 8 ( Introduction of Trigonometry)

NCERT Solutions for Class 10 Maths Chapter 8 Introduction of  Trigonometry of exercise 8.4 for all boards. We have updated all the contents for the new academic session 2020-2021.

In this chapter, you have studied the following points:

1. In a right triangle ABC, right-angled at B

•  sin A=side opposite to angle A /hypotenuse
• cos A=side adjacent to angle A/hypotenuse
• tan A=side opposite to angle A/side adjacent to angle A

1. cosec A=1/sin A;        sec A=1/cos A;         tan A=1/cot A;       tan A=sin A/cos A;
2. If one of the trigonometric ratios of an acute angle is known, the remaining trigonometric ratios of the angle can be easily determined.
3. The values of trigonometric ratios for angles 0°, 30°, 45°, 60°, and 90°.
4. The value of sin A or cos A never exceeds 1, whereas the value of sec A or cosec A is always greater than or equal to 1.
5. sin (90° – A) = cos A, cos (90° – A) = sin A;
   tan (90° – A) = cot A, cot (90° – A) = tan A;
   sec (90° – A) = cosec A, cosec (90° – A) = sec A.