Question

if sin 49°=3÷4 find sin 581°​

Answer 1

Answer:

Let f(x) = sin x

Now f’(x) = cos x

Now f(x+ δx) - f(x) = f’(x).δx

f(x+ δx) - f(x) = cos x . δx

Putting x = 45°, δx = 4° = 4. 0.01745 radian = 0.0698 radian ( since 1° = 0.01745 radian)

f(49°) - f(45°) = cos 45° . 0.0698

sin 49° - sin 45° = cos 45° . 0.0698

sin 49° - 1/√2 = 1/√2 . 0.0698

sin 49° - 0.707 = 0.707 . 0.698

sin 49° = 0.707 + 0.049

sin 49° = 0.756 (approx)