4. 求值:(1)lg5+lg2+log23⋅log34−(94)−12+31lg3lg5+lg2+\log _{2}\sqrt{3}\cdot lo{g_3}4-{({\frac{9}{4}})^{-\frac{1}{2}}}+{3^{\frac{1}{lg3}}}lg5+lg2+log23⋅log34−(49)−21+3lg31;(2)cos10∘−3cos100∘1−cos80∘\frac{\cos 10\circ -\sqrt{3}\cos 100\circ }{\sqrt{1-\cos 80\circ }}1−cos80∘cos10∘−3cos100∘.