If $\sin x=\frac{\sqrt{5}}{3}$ and $0
Given: $\sin x=\frac{\sqrt{5}}{3}$
To find: $\sin 2 x$
We know that
sin2x = 2 sinx cosx …(i)
Here, we don’t have the value of cos x. So, firstly we have to find the value of cosx
We know that,
$\sin ^{2} x+\cos ^{2} x=1$
Putting the values, we get
$\left(\frac{\sqrt{5}}{3}\right)^{2}+\cos ^{2} x=1$
$\Rightarrow \frac{5}{9}+\cos ^{2} x=1$
$\Rightarrow \cos ^{2} x=1-\frac{5}{9}$
$\Rightarrow \cos ^{2} x=\frac{9-5}{9}$
$\Rightarrow \cos ^{2} x=\frac{4}{9}$
$\Rightarrow \cos x=\sqrt{\frac{4}{9}}$
$\Rightarrow \cos x=\pm \frac{2}{3}$
It is given that $0 $\Rightarrow \cos \mathrm{X}=\frac{2}{3}$ Putting the value of sinx and cosx in eq. (i), we get $\sin 2 x=2 \sin x \cos x$ $\sin 2 x=2 \times \frac{\sqrt{5}}{3} \times \frac{2}{3}$ $\therefore \sin 2 x=\frac{4 \sqrt{5}}{9}$