If sin2a=-3/4 then a=?

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Answer 1 · 2018-02-22T07:58:34

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

#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!