数学课前练习

1. 已知\(\sin\alpha+\cos\alpha=\displaystyle \frac{1}{5}(0<\alpha<\pi)\),则\(\tan2\alpha=\)()
2. 已知\(\cos(\alpha-\beta)=\displaystyle \frac{7}{12}\),\(\sin\alpha\sin\beta=\displaystyle \frac{1}{3}\),则\(\sin2\alpha\sin2\beta=\)()