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已知等比数列{an}中,各项都是正数,且成等差数列,则等于A.B.C.D.
试题详情
已知等比数列{a
n}中,各项都是正数,且
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAGEAAAAjCAYAAACElmTEAAAAAXNSR0IArs4c6QAAAARnQU1BAACx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)
成等差数列,则
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACMAAAAxCAYAAABQxxDJAAAAAXNSR0IArs4c6QAAAARnQU1BAACx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)
等于( )
A.
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQNJREFU
SEvFlI0NhCAMhWEj9nELhmCJ7sAAzEHiDizRa1HwjzvgDk8SE01qv76+Uol0xOAjpWzLyPDRh8hN
KduimlJtQf3w4FALjS50kgrhfXAP7Ds9FTjFga8Xd4Hn/MTQDpO+Xds9wh1w7miumBlUwPp9Ozx4
n5Vyz4LTWX0V7oHtePdA0YOPnrMF/1J+ro7FJBeqyg8/fztwKcnBf1puW/KbBi4DAjoNuL8sv8Pt
tM7ElDElzz1cr/ECjwtmG6qWu5xI1tr4apRAZeb4fobzhB9yrvaNW6+xA4v6Pbx8W5b2j4NTsom6
x+r71mt9YzZFzEahUOYZOFfI6h9RntrTCn8BwYR+BrKgjSYAAAAASUVORK5CYII=
)
B.
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQFJREFU
SEvFlI0NhCAMhWEj9nELhmAJdmAA5mjiDizRa1Hw5/AOPDhJSMRgv772WYm0ROclpayLyPDei8hV
IetuVYXaLrXDg0ctNPrQSCpcb4OD5b7THgTP8YmhPSZ9u7ID2hFwrqiFtT7MoATW83B4AMhKOYPg
dVb/FQ6W23Gxs6Jj4z/2nFvwL+VnP7KYlPNX5Xe8f6n80H8ablvwQYbLgIBeW0zWi5P1Z7ibVk9M
OVRJOdj333iBxwGzmerCR8UOOOfie6MEKjPH5zOcHX6ISabjc7/xGiuwqN/Dy3/LUv5+cAo2UfVY
fdt4vWPpwjezUSiUeQbO+bD6R5SnYtTCX14ahqxGLOQaAAAAAElFTkSuQmCC
)
C.
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACcAAAASCAYAAADYFMcrAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAT9JREFU
SEvNlW0NxCAMhsHR/MwFIjCBBwSgg+Q8YKJHx0b4LLAfZCSXWzYoz/u2FA5+sM2Dcz63I8LtHp5s
asu5WVOh5ietwTkDwqvBRUzZ+V3SmVaF9fgTBhwRZQHOgorB/LMP3uXzAM1vKC5+CDEokRVcRxgD
5zKVVq3DOWuzGM4I0r0MjhCW1xwqoNLac65M4SBOCkcJi3DoWKvm4vunnrJ/Ba0KJd0PratfkYmw
fNZ9MITplPOMc1ma2gwUXCqskkDWyxDOgRFtN1PMLlwhrPaXqpcBnFUCeqaP4WphBRxOWD+tuDE6
np2lR4g+7/53Rr6Wcy1hDNIeQ/U4oqm2D01Ir9b6WikPBof8Xc8lXE/YvuvrcjC4l8JRwvbBeajT
ZwbdW7i+3l2lb1b95AHskN+EQ0Ho3iede9yehfsDL9xnWKqKNdsAAAAASUVORK5CYII=
)
D.
相关试题
-
已知数列{an}是各项均为正数的等比数列,若
,则an等于( )
A.2n-1
B.23-n
C.2n-2
D.2n
-
已知数列{an}是各项均为正数的等比数列,若
,则an等于( )
A.2n-1
B.23-n
C.2n-2
D.2n
-
已知等比数列{an}中,各项都是正数,且
成等差数列,则
等于( )
A.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQNJREFU
SEvFlI0NhCAMhWEj9nELhmCJ7sAAzEHiDizRa1HwjzvgDk8SE01qv76+Uol0xOAjpWzLyPDRh8hN
KduimlJtQf3w4FALjS50kgrhfXAP7Ds9FTjFga8Xd4Hn/MTQDpO+Xds9wh1w7miumBlUwPp9Ozx4
n5Vyz4LTWX0V7oHtePdA0YOPnrMF/1J+ro7FJBeqyg8/fztwKcnBf1puW/KbBi4DAjoNuL8sv8Pt
tM7ElDElzz1cr/ECjwtmG6qWu5xI1tr4apRAZeb4fobzhB9yrvaNW6+xA4v6Pbx8W5b2j4NTsom6
x+r71mt9YzZFzEahUOYZOFfI6h9RntrTCn8BwYR+BrKgjSYAAAAASUVORK5CYII=
)
B.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQFJREFU
SEvFlI0NhCAMhWEj9nELhmAJdmAA5mjiDizRa1Hw5/AOPDhJSMRgv772WYm0ROclpayLyPDei8hV
IetuVYXaLrXDg0ctNPrQSCpcb4OD5b7THgTP8YmhPSZ9u7ID2hFwrqiFtT7MoATW83B4AMhKOYPg
dVb/FQ6W23Gxs6Jj4z/2nFvwL+VnP7KYlPNX5Xe8f6n80H8ablvwQYbLgIBeW0zWi5P1Z7ibVk9M
OVRJOdj333iBxwGzmerCR8UOOOfie6MEKjPH5zOcHX6ISabjc7/xGiuwqN/Dy3/LUv5+cAo2UfVY
fdt4vWPpwjezUSiUeQbO+bD6R5SnYtTCX14ahqxGLOQaAAAAAElFTkSuQmCC
)
C.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACcAAAASCAYAAADYFMcrAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAT9JREFU
SEvNlW0NxCAMhsHR/MwFIjCBBwSgg+Q8YKJHx0b4LLAfZCSXWzYoz/u2FA5+sM2Dcz63I8LtHp5s
asu5WVOh5ietwTkDwqvBRUzZ+V3SmVaF9fgTBhwRZQHOgorB/LMP3uXzAM1vKC5+CDEokRVcRxgD
5zKVVq3DOWuzGM4I0r0MjhCW1xwqoNLac65M4SBOCkcJi3DoWKvm4vunnrJ/Ba0KJd0PratfkYmw
fNZ9MITplPOMc1ma2gwUXCqskkDWyxDOgRFtN1PMLlwhrPaXqpcBnFUCeqaP4WphBRxOWD+tuDE6
np2lR4g+7/53Rr6Wcy1hDNIeQ/U4oqm2D01Ir9b6WikPBof8Xc8lXE/YvuvrcjC4l8JRwvbBeajT
ZwbdW7i+3l2lb1b95AHskN+EQ0Ho3iede9yehfsDL9xnWKqKNdsAAAAASUVORK5CYII=
)
D.
-
已知等比数列{an}中,各项都是正数,且
成等差数列,则
等于( )
A.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAADrSURBVEhL1ZRBDoQgDEV7LhYcx31vwpqDsOUg
LjhKxwIiDkQ7UTRDYqKh8vjtb4EGLAAg0TOAHcGSJYuSnFTF/Bk8WNKgyYYfZXbCG+UeNw9oSysi
pb1snsCXOPTnl9vBWVT5yROyGfN3VXPeuB8evC9K+drBaoKsfji8yRNnWarc41HPYrcGR27n89Yq
PKt8V3+iB+GBrEaq/Xod7qbcRlMpQS/tHlszX4Y75yLUKCBl5vj+DWeH71o0t2yCxwGzGUvSy43T
YgaS+hreN2xK/62zfVoEsPpXZvtsFIEy78A55az+FeWrD6TwD4gIxzM17L0YAAAAAElFTkSuQmCC
)
B.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAADpSURBVEhL1ZRLDoQgEET7XCw4jntuwpqDsO2D
uOAoNTY/dXQME0UjCYkE5FFF0YQOjYjQ1DuwI7ilta1q2Wmx5mXw4KBJw4U/Ze4s3yhnM2dAOxRE
sr1OdoCLKMP5iAwjYczjxZ3LxPXwwFyVygmC06Csvjt8cyvicqtyNgdvttq5RhylXfYrv92rfHX/
wI3wAKcNSvTEq/NwP+RnNFTv92xnsw3zabj3PkKtIig7xu9vuCR8FY8pdDJO8Fhg5mD9yNFx9YkO
JPVL+H5gk/2X1vZhEiDqH6nto1UgZZ+Bi+Wi/hHlJRSt8A/BydM2Nzab2gAAAABJRU5ErkJggg==
)
C.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACcAAAASCAYAAADYFMcrAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAExSURBVEhL3ZVNDoQgDIV7LhYcxz03Yc1B2HIQ
FxylQ1EZfitsRjMkJkZ59eujrYAPLADAqesBtgg2s+Z2zURa2PNHcN6gvOpAuQUPsq1OfetIGvRM
lMa5gTYcq0OVgoX7ADnkC0G67yi59OKIAUySBRyjBfS+yNKpdTjvXBHDG4nAuJfDcdqyIche7lhH
ztVHeBOHbYhMm+DIsTh7Krj0vDubVCiKdrHuh+0cXK4tnTsbQ5pBOc84V9RQvyuGcJW2mXNsvdzC
eTSy72aO2Ydrte0Q5urlBs4piY3pdjtHzJb4enA9bQVH9OvdSl8lx4tyPROx1kYoLQCF3uN9DTfS
AuYDkJtxzFDtN011vNHBw70cjtP+9N+6heTJvVf+W3ctEIR+JxwdKbn3Sueusp2F+wCpb8kJ//Yj
fAAAAABJRU5ErkJggg==
)
D.
-
已知等比数列{an}中,各项都是正数,且
成等差数列,则
等于( )
A.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAADiSURBVEhL7ZS9DcQgDIU9FwXjpPcm1AxC60FS
MIovBoeEI3eHRH6aexIKBONPz0YAXyAA6Bsaf6okcY/+cObo2YJlH3U9oAZOmHssw3peETmqbP6A
L3FIOv+iCi6myiFiFI6ud1GycT48EhWnouhtcX85vJFUudc5ofbqcKBG1ZK9T5J8q4F7nVf9vxUe
2VtcKJvG4WHSFkz64xhO2OYehocQ0tcZYOPmNH+Hyw2vzmmeHJUemO0i9ZS2UapAdr+HH1/YXP62
PgOalsTifg//plPhszMMxj0DF4n7x+CiPjjzC4gIxzOspkD8AAAAAElFTkSuQmCC
)
B.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAADeSURBVEhL7ZRNDoQgDIU5FwuO456bsOYgbHsQ
Fxyl44OKOqghwZ+NLyFOpdMvr21UfIOUUm1H8i8VCrfogzNHz0YZ9lHiDlVwsnnGOMbzjMhZ5fIG
OExZkoDYgiPxKgsX18MjUXEKRW+K+9vhldDlVudkZVZ7p7RzK9wdCfXmvz3rfDP/R+GRvbETZVE/
PAwyhkFe7MPJ1rW74SGE9HRasXZj+v0Px4Zv1mNaOsQ5K31glkU62KNzpQ5k92v4/sLm9tf96dAw
FYb7NfxMl8JHp1lp9w4cgvvX4FAbnPkHwcnTNrgdIAcAAAAASUVORK5CYII=
)
C.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACcAAAASCAYAAADYFMcrAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAEpSURBVEhL7VQ7DsMgDOVcDBwnOzdh5iCsHKQD
R3ExEMTHOEmlphn6JCRq/MzzM6mAH0AIcW6V/FuBF5/BX9yIa+KCBbXPWfsUugyvMx+XshBKmMIk
bsGNWR50DcR9TFjqi0XIM2yuHuQaXJOdOIYrIISuS6+viwvedzWCVax7rTiO2/uL9jIdL50bcVBn
GmuLhluz0LE086FojZNLx0HMYN2PQO4KLbfPKh+GsouBnHGue0M0luIG7pTFvpdDcQGsot1sQYub
uXMW914OxHmtYDLdbeUJbCVAi6O4Qxaq/+CvJAId785KrnMu/TRSgDSvtB/FrbgCN7mzvFaXc6A/
mmG8ycHsHp7v4Lizv1/EFi9G91pxHG4V9zIShDTPFIdA9x4rDnFOHMAbqW/JCQ9AfXUAAAAASUVO
RK5CYII=
)
D.
-
已知等比数列{an}中,各项都是正数,且
成等差数列,则
等于( )
A.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQNJREFU
SEvFlI0NhCAMhWEj9nELhmCJ7sAAzEHiDizRa1HwjzvgDk8SE01qv76+Uol0xOAjpWzLyPDRh8hN
KduimlJtQf3w4FALjS50kgrhfXAP7Ds9FTjFga8Xd4Hn/MTQDpO+Xds9wh1w7miumBlUwPp9Ozx4
n5Vyz4LTWX0V7oHtePdA0YOPnrMF/1J+ro7FJBeqyg8/fztwKcnBf1puW/KbBi4DAjoNuL8sv8Pt
tM7ElDElzz1cr/ECjwtmG6qWu5xI1tr4apRAZeb4fobzhB9yrvaNW6+xA4v6Pbx8W5b2j4NTsom6
x+r71mt9YzZFzEahUOYZOFfI6h9RntrTCn8BwYR+BrKgjSYAAAAASUVORK5CYII=
)
B.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQFJREFU
SEvFlI0NhCAMhWEj9nELhmAJdmAA5mjiDizRa1Hw5/AOPDhJSMRgv772WYm0ROclpayLyPDei8hV
IetuVYXaLrXDg0ctNPrQSCpcb4OD5b7THgTP8YmhPSZ9u7ID2hFwrqiFtT7MoATW83B4AMhKOYPg
dVb/FQ6W23Gxs6Jj4z/2nFvwL+VnP7KYlPNX5Xe8f6n80H8ablvwQYbLgIBeW0zWi5P1Z7ibVk9M
OVRJOdj333iBxwGzmerCR8UOOOfie6MEKjPH5zOcHX6ISabjc7/xGiuwqN/Dy3/LUv5+cAo2UfVY
fdt4vWPpwjezUSiUeQbO+bD6R5SnYtTCX14ahqxGLOQaAAAAAElFTkSuQmCC
)
C.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACcAAAASCAYAAADYFMcrAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAT9JREFU
SEvNlW0NxCAMhsHR/MwFIjCBBwSgg+Q8YKJHx0b4LLAfZCSXWzYoz/u2FA5+sM2Dcz63I8LtHp5s
asu5WVOh5ietwTkDwqvBRUzZ+V3SmVaF9fgTBhwRZQHOgorB/LMP3uXzAM1vKC5+CDEokRVcRxgD
5zKVVq3DOWuzGM4I0r0MjhCW1xwqoNLac65M4SBOCkcJi3DoWKvm4vunnrJ/Ba0KJd0PratfkYmw
fNZ9MITplPOMc1ma2gwUXCqskkDWyxDOgRFtN1PMLlwhrPaXqpcBnFUCeqaP4WphBRxOWD+tuDE6
np2lR4g+7/53Rr6Wcy1hDNIeQ/U4oqm2D01Ir9b6WikPBof8Xc8lXE/YvuvrcjC4l8JRwvbBeajT
ZwbdW7i+3l2lb1b95AHskN+EQ0Ho3iede9yehfsDL9xnWKqKNdsAAAAASUVORK5CYII=
)
D.
-
已知等比数列{an}中,各项都是正数,且
成等差数列,则
等于( )
A.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQNJREFU
SEvFlI0NhCAMhWEj9nELhmCJ7sAAzEHiDizRa1HwjzvgDk8SE01qv76+Uol0xOAjpWzLyPDRh8hN
KduimlJtQf3w4FALjS50kgrhfXAP7Ds9FTjFga8Xd4Hn/MTQDpO+Xds9wh1w7miumBlUwPp9Ozx4
n5Vyz4LTWX0V7oHtePdA0YOPnrMF/1J+ro7FJBeqyg8/fztwKcnBf1puW/KbBi4DAjoNuL8sv8Pt
tM7ElDElzz1cr/ECjwtmG6qWu5xI1tr4apRAZeb4fobzhB9yrvaNW6+xA4v6Pbx8W5b2j4NTsom6
x+r71mt9YzZFzEahUOYZOFfI6h9RntrTCn8BwYR+BrKgjSYAAAAASUVORK5CYII=
)
B.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQFJREFU
SEvFlI0NhCAMhWEj9nELhmAJdmAA5mjiDizRa1Hw5/AOPDhJSMRgv772WYm0ROclpayLyPDei8hV
IetuVYXaLrXDg0ctNPrQSCpcb4OD5b7THgTP8YmhPSZ9u7ID2hFwrqiFtT7MoATW83B4AMhKOYPg
dVb/FQ6W23Gxs6Jj4z/2nFvwL+VnP7KYlPNX5Xe8f6n80H8ablvwQYbLgIBeW0zWi5P1Z7ibVk9M
OVRJOdj333iBxwGzmerCR8UOOOfie6MEKjPH5zOcHX6ISabjc7/xGiuwqN/Dy3/LUv5+cAo2UfVY
fdt4vWPpwjezUSiUeQbO+bD6R5SnYtTCX14ahqxGLOQaAAAAAElFTkSuQmCC
)
C.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACcAAAASCAYAAADYFMcrAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAT9JREFU
SEvNlW0NxCAMhsHR/MwFIjCBBwSgg+Q8YKJHx0b4LLAfZCSXWzYoz/u2FA5+sM2Dcz63I8LtHp5s
asu5WVOh5ietwTkDwqvBRUzZ+V3SmVaF9fgTBhwRZQHOgorB/LMP3uXzAM1vKC5+CDEokRVcRxgD
5zKVVq3DOWuzGM4I0r0MjhCW1xwqoNLac65M4SBOCkcJi3DoWKvm4vunnrJ/Ba0KJd0PratfkYmw
fNZ9MITplPOMc1ma2gwUXCqskkDWyxDOgRFtN1PMLlwhrPaXqpcBnFUCeqaP4WphBRxOWD+tuDE6
np2lR4g+7/53Rr6Wcy1hDNIeQ/U4oqm2D01Ir9b6WikPBof8Xc8lXE/YvuvrcjC4l8JRwvbBeajT
ZwbdW7i+3l2lb1b95AHskN+EQ0Ho3iede9yehfsDL9xnWKqKNdsAAAAASUVORK5CYII=
)
D.
-
已知等比数列{an}中,各项都是正数,且
成等差数列,则
等于( )
A.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQNJREFU
SEvFlI0NhCAMhWEj9nELhmCJ7sAAzEHiDizRa1HwjzvgDk8SE01qv76+Uol0xOAjpWzLyPDRh8hN
KduimlJtQf3w4FALjS50kgrhfXAP7Ds9FTjFga8Xd4Hn/MTQDpO+Xds9wh1w7miumBlUwPp9Ozx4
n5Vyz4LTWX0V7oHtePdA0YOPnrMF/1J+ro7FJBeqyg8/fztwKcnBf1puW/KbBi4DAjoNuL8sv8Pt
tM7ElDElzz1cr/ECjwtmG6qWu5xI1tr4apRAZeb4fobzhB9yrvaNW6+xA4v6Pbx8W5b2j4NTsom6
x+r71mt9YzZFzEahUOYZOFfI6h9RntrTCn8BwYR+BrKgjSYAAAAASUVORK5CYII=
)
B.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQFJREFU
SEvFlI0NhCAMhWEj9nELhmAJdmAA5mjiDizRa1Hw5/AOPDhJSMRgv772WYm0ROclpayLyPDei8hV
IetuVYXaLrXDg0ctNPrQSCpcb4OD5b7THgTP8YmhPSZ9u7ID2hFwrqiFtT7MoATW83B4AMhKOYPg
dVb/FQ6W23Gxs6Jj4z/2nFvwL+VnP7KYlPNX5Xe8f6n80H8ablvwQYbLgIBeW0zWi5P1Z7ibVk9M
OVRJOdj333iBxwGzmerCR8UOOOfie6MEKjPH5zOcHX6ISabjc7/xGiuwqN/Dy3/LUv5+cAo2UfVY
fdt4vWPpwjezUSiUeQbO+bD6R5SnYtTCX14ahqxGLOQaAAAAAElFTkSuQmCC
)
C.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACcAAAASCAYAAADYFMcrAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAT9JREFU
SEvNlW0NxCAMhsHR/MwFIjCBBwSgg+Q8YKJHx0b4LLAfZCSXWzYoz/u2FA5+sM2Dcz63I8LtHp5s
asu5WVOh5ietwTkDwqvBRUzZ+V3SmVaF9fgTBhwRZQHOgorB/LMP3uXzAM1vKC5+CDEokRVcRxgD
5zKVVq3DOWuzGM4I0r0MjhCW1xwqoNLac65M4SBOCkcJi3DoWKvm4vunnrJ/Ba0KJd0PratfkYmw
fNZ9MITplPOMc1ma2gwUXCqskkDWyxDOgRFtN1PMLlwhrPaXqpcBnFUCeqaP4WphBRxOWD+tuDE6
np2lR4g+7/53Rr6Wcy1hDNIeQ/U4oqm2D01Ir9b6WikPBof8Xc8lXE/YvuvrcjC4l8JRwvbBeajT
ZwbdW7i+3l2lb1b95AHskN+EQ0Ho3iede9yehfsDL9xnWKqKNdsAAAAASUVORK5CYII=
)
D.
-
已知等比数列{an}中,各项都是正数,且
成等差数列,则
等于________.
-
已知等比数列{an}中,各项都是正数,且
成等差数列,则
等于( )
A.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQNJREFU
SEvFlI0NhCAMhWEj9nELhmCJ7sAAzEHiDizRa1HwjzvgDk8SE01qv76+Uol0xOAjpWzLyPDRh8hN
KduimlJtQf3w4FALjS50kgrhfXAP7Ds9FTjFga8Xd4Hn/MTQDpO+Xds9wh1w7miumBlUwPp9Ozx4
n5Vyz4LTWX0V7oHtePdA0YOPnrMF/1J+ro7FJBeqyg8/fztwKcnBf1puW/KbBi4DAjoNuL8sv8Pt
tM7ElDElzz1cr/ECjwtmG6qWu5xI1tr4apRAZeb4fobzhB9yrvaNW6+xA4v6Pbx8W5b2j4NTsom6
x+r71mt9YzZFzEahUOYZOFfI6h9RntrTCn8BwYR+BrKgjSYAAAAASUVORK5CYII=
)
B.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAB8AAAASCAYAAACjMAXnAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAQFJREFU
SEvFlI0NhCAMhWEj9nELhmAJdmAA5mjiDizRa1Hw5/AOPDhJSMRgv772WYm0ROclpayLyPDei8hV
IetuVYXaLrXDg0ctNPrQSCpcb4OD5b7THgTP8YmhPSZ9u7ID2hFwrqiFtT7MoATW83B4AMhKOYPg
dVb/FQ6W23Gxs6Jj4z/2nFvwL+VnP7KYlPNX5Xe8f6n80H8ablvwQYbLgIBeW0zWi5P1Z7ibVk9M
OVRJOdj333iBxwGzmerCR8UOOOfie6MEKjPH5zOcHX6ISabjc7/xGiuwqN/Dy3/LUv5+cAo2UfVY
fdt4vWPpwjezUSiUeQbO+bD6R5SnYtTCX14ahqxGLOQaAAAAAElFTkSuQmCC
)
C.![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACcAAAASCAYAAADYFMcrAAAAAXNSR0IArs4c6QAAAARnQU1BAACx
jwv8YQUAAAAgY0hSTQAAeiYAAICEAAD6AAAAgOgAAHUwAADqYAAAOpgAABdwnLpRPAAAAT9JREFU
SEvNlW0NxCAMhsHR/MwFIjCBBwSgg+Q8YKJHx0b4LLAfZCSXWzYoz/u2FA5+sM2Dcz63I8LtHp5s
asu5WVOh5ietwTkDwqvBRUzZ+V3SmVaF9fgTBhwRZQHOgorB/LMP3uXzAM1vKC5+CDEokRVcRxgD
5zKVVq3DOWuzGM4I0r0MjhCW1xwqoNLac65M4SBOCkcJi3DoWKvm4vunnrJ/Ba0KJd0PratfkYmw
fNZ9MITplPOMc1ma2gwUXCqskkDWyxDOgRFtN1PMLlwhrPaXqpcBnFUCeqaP4WphBRxOWD+tuDE6
np2lR4g+7/53Rr6Wcy1hDNIeQ/U4oqm2D01Ir9b6WikPBof8Xc8lXE/YvuvrcjC4l8JRwvbBeajT
ZwbdW7i+3l2lb1b95AHskN+EQ0Ho3iede9yehfsDL9xnWKqKNdsAAAAASUVORK5CYII=
)
D.