If sin2a=-3/4 then a=?

1 Answer
Feb 22, 2018

a\ =\ -\frac{1}{2}sin^{-1}(\frac{3}{4})

Explanation:

sin(2a)=-\frac{3}{4}

By taking inverse function on both sides,

2a =sin^{-1}(-\frac{3}{4})

Divide both sides by 2:

a\ =\ \frac{1}{2}sin^{-1}(-\frac{3}{4})

Since, sin is a odd function, i.e sin(-x)=-sin(x) we have:

a\ =\ -\frac{1}{2}sin^{-1}(\frac{3}{4})

That's it!