Question

Which of the following correctly expresses sin (70) + sin(30) as a product?

Answer 1

Answer:

2sin50 cos20

Step-by-step explanation:

We need to write sin (70) + sin(30) as a product. The formula used here is :

$\sin A+\sin B=2\sin (\dfrac{A+B}{2})\cos(\dfrac{a-b}{2})$

Here, A = 70 and B = 30

So,

$\sin 70+\sin 30=2\sin (\dfrac{70+30}{2})\cos(\dfrac{70-30}{2})\\\\\sin 70+\sin 30=2\sin 50\cos20$

So, the value of sin (70) + sin(30) is 2sin50 cos20. Hence, the correct option is  (c).