Question

prove that sin 70°+ sin 50°= √3 cos 10°​

Answer 1

Answer:

Sin(A+B) = Sin(A)Cos(B)+Cos(A)Sin(B)

2) Sin(A-B) = Sin(A)Cos(B)-Cos(A)Sin(B)

Now we write our expression as Sin(60-10) - Sin(60+10) +Sin(10).

On applying the above formulas we get:

Sin(60)Cos(10) - Cos(60)Sin(10) -{Sin(60)Cos(10) + Cos(60)Sin(10)} + Sin(10)

On simplifying we get:

-2*Cos(60)Sin(10) + Sin(10)

Using Cos(60) = 1/2 in above expression we get:

-2*(1/2)*Sin(10) + Sin(10)

= 0