Question

2. If cosA=4/5, find cosec A​

Answer 1

Answer:

sin²A+cos²A = 1

sin²A+(4/5)² = 1

sin²A+(16/25) = 1

sin²A = (16-1/25)

sin²A = (25-16/25)

sin²A = (9/25)

sinA = 3/5

since. cosec A = 1/sinA

therefore. cosecA =5/3

Answer 2

Answer:

cosec A= 5/3

Step-by-step explanation:

In triangle ABC,right angled at B

cosA= BC/AC. (since cos thetha=side adjacent to angle thetha/ hypotenuse)

By PGT,

(AC)^2=(BC)^2+(AB)^2

5^2=(BC)^2+4^2

25=(BC)^2+16

(BC)^2=9

BC=9cm

cosecA=hypotenuse/side opp. to angle A

=AC/BC

=5/3