4.
如图,已知正方形ABCD的边长为2,在CD的延长线上取一点E,以CE为直径作圆交AD的延长线于点F,连接FB交圆于另一点G,且GB=DF.
(1)证明:GF=CE.
(2)试求五边形ABCFE的面积.
(1)证明:GF=CE.
(2)试求五边形ABCFE的面积.
5.已知代数式$\sqrt{1-x}$+$\sqrt{\frac{1}{x}}$在实数范围内有意义,则x的取值范围是( )
| A. | x≥1 | B. | 0<x≤1 | C. | x>0 | D. | 0≤x≤1 |
4.下列四对数值中是方程2x-y=1的解的是( )
0 285043 285051 285057 285061 285067 285069 285073 285079 285081 285087 285093 285097 285099 285103 285109 285111 285117 285121 285123 285127 285129 285133 285135 285137 285138 285139 285141 285142 285143 285145 285147 285151 285153 285157 285159 285163 285169 285171 285177 285181 285183 285187 285193 285199 285201 285207 285211 285213 285219 285223 285229 285237 366461
| A. | $\left\{\begin{array}{l}{x=2}\\{y=0}\end{array}\right.$ | B. | $\left\{\begin{array}{l}{x=-1}\\{y=-1}\end{array}\right.$ | C. | $\left\{\begin{array}{l}{x=0}\\{y=-1}\end{array}\right.$ | D. | $\left\{\begin{array}{l}{x=-1}\\{y=1}\end{array}\right.$ |