[tex]\text{Il aflam pe }\cos x\text{ dn teorema fundamentala a trigonometriei.}\\
\sin^2 x+\cos^2 x=1\\
\dfrac{9}{25}+\cos^2 x=1\\
\cos^2 x=1-\dfrac{9}{25}\\
\cos^2 x=\dfrac{16}{25}\\
\cos x=\pm \dfrac{4}{5}\\
x\in \left(\dfrac{\pi}{2},\pi\right)\Rightarrow \cos x=-\dfrac{4}{5}\\
\sin2x=2\sin x\cos x=2\cdot \dfrac{3}{5}\cdot \left(-\dfrac{4}{5}\right)=\boxed{-\dfrac{24}{25} }\\
tg\ x=\dfrac{\sin x}{\cos x}=\dfrac{\frac{3}{5}}{-\frac{4}{5}}=\boxed{-\dfrac{3}{4}} [/tex]
