Question

find the exact value of tan 2 theta given sin theta=3/5,0 12 years ago

Answer 1

First : calculate :
\[\cos\theta\]
by using :
\[1=\cos^2\theta+\sin^2\theta.\]
Don't forget that :
\[0<\theta<\frac\pi2\]
so :
\[\cos\theta \geq 0.\]
And then :
\[\tan\theta=\frac{\sin\theta }{\cos \theta}=\cdots\]
And in the end use the
\[\tan2\theta\]
formula !