Question

COS A
11.6 Summary
In this chapter, you have studied the following points:
1. In a right triangle ABC, right-angled at B.
side opposite to angle A
side adjacent to angle A
sin A
COS A
hypotenuse
hypotenuse
side opposite to angle A
side adjacent to angle A
1
1
1
sin A
2. cosee A =
: sec A
:tan A
tan A=
sin A
COS A
cot A
3. If one of the trigonometric ratios of an acute angle is known, the remaining trigonometric
ratios of the angle can be easily determined.
4. The values of trigonometric ratios for angles 0°, 30°, 45°, 60° and 90°.
5. 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.
6. 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.
7. Sin- A+ cos-A=1,
sec-A-tan-A=1 for 0° <A< 90°,
cosec-A= 1 + cot? A for 0° <A<90°.​

Answer 1

Answer:

1

1

sin A

2. cosee A =

: sec A

:tan A

tan A=

sin A

COS A

cot A

3. If one of the trigonometric ratios of an acute angle is known, the remaining trigonometric

ratios of the angle can be easily determined.

4. The values of trigonometric ratios for angles 0°, 30°, 45°, 60° and 90°.

5. 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.

6. 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.

7. Sin- A+ cos-A=1,

sec-A-tan-A=1 for 0° <A< 90°,

cosec-A= 1 + cot? A for 0° <A<90