Write the value of the expression `(1-4sin1 0^0sin7 0^0)/(2sin1 0^0)`

Explanation

`frac{1-4 sin 10 sin 70}{2 sin 10}`


`[2 sin A sin B=cos (A-B)-cos (A+B)] `


`=frac{1-2[cos (10-70)-cos (10+70)]}{2 sin 10}`


`[cos (-theta)=cos theta] `


`=frac{1-2 cos 60+2 cos 80}{2 sin 10}`


`=frac{1-2(1 / 2)+2 cos 80}{2 sin 10}=frac{cos 80}{sin 10}`


`=[frac{cos (90-theta)=sin theta, therefore cos (90-10)}{sin 10}=1 . sin 10]`


`=(sin10)/(sin10)=1`