共50条信息
在 \(\vartriangle ABC\) 中,若 \({a}^{2}=b\left(b+c\right) \) .
\((2)\)若\(a= \sqrt{3}b \) ,判断 \(\vartriangle ABC\) 的形状
在\(\triangle ABC\)中,已知内角\(A\),\(B\),\(C\)对边分别是\(a\),\(b\),\(c\),且\(2c\cos B=2a+b\).
在\(∆ABC \)中,内角\(A \),\(B \),\(C \)的对边分别为\(a \),\(b \),\(c \),且\(c\cos B+b\cos C=2a\cos A \).
\((1)\)求\(A \);
\((2)\)若\(a=2 \),且\(∆ABC \)的面积为\(\sqrt{3} \),求\(∆ABC \)的周长.
求值:
\((1)\sin 50{}^\circ (1+\sqrt{3}\sin 10{}^\circ )\)
\((2)\dfrac{2{{\cos }^{2}}42{}^\circ +\sin 75{}^\circ \cos 81{}^\circ -1}{\cos 6{}^\circ -\cos 75{}^\circ \cos 81{}^\circ }\)
进入组卷