若等比数列{an}中，a3=3,a5=9,则此数列的公比为多少？

\u82e5\u7b49\u6bd4\u6570\u5217\u4e2d\uff0ca3=3\uff0ca5=9\uff0c\u5219\u6b64\u6570\u5217\u7684\u516c\u6bd4\u4e3a\u591a\u5c11

\u8bbe\u516c\u6bd4x
3*x*x=9
\u6240\u4ee5x=\u221a3

a5=a3q^2 a3=3,a5=9
\u6240\u4ee5q=\u221a3 (\u7531\u9898\u77e5\u9053a5>a3,\u6240\u4ee5\u6b64\u7b49\u6bd4\u6570\u5217\u662f\u9012\u589e\u6570\u5217\u3002\u6545\u820d\u53bb-\u221a3.\uff09
\u6240\u4ee5\u516c\u6bd4\u4e3a\u221a3

q^2=3
q=+-根3

a5-a3=q^2=3
q=±√3

绛夋瘮鏁板垪{an}涓,鑻3=3,a6=24,鍒檃7鐨勫间负___.
绛旓細绛夋瘮鏁板垪{an}涓紝a3=3锛宎6=24锛宎3q3=a6锛屾墍浠24=3×q3锛屾墍浠=2锛屸埓a7=a3q4=3×24=48 鏁呯瓟妗堜负锛48

鍦绛夋瘮鏁板垪{an}涓,鑻3=3,a9=15,鍒檃15=___.
绛旓細瑙ｏ細鈭靛湪绛夋瘮鏁板垪{an}涓璦3=3锛宎9=15锛屽張鐢辩瓑姣旀暟鍒楃殑鎬ц川鍙緱a92=a3a15锛屸埓152=3a15锛岃В寰梐15=75 鏁呯瓟妗堜负锛75

鍦绛夋瘮鏁板垪{an}涓嫢a3=3,a9=75鍒檃15=
绛旓細鍥犱负a3=a1d骞虫柟锛宎9=a1d鐨8娆℃柟锛屾墍浠9/a3=d鐨6娆℃柟=25锛沘15=a9d鐨6娆℃柟=75脳25=1875

绛夋瘮鏁板垪{an}涓嫢a3=3鍒欐鏁板垪鐨勫墠5椤圭Н涓
绛旓細a1 a2 a3 a4 a5=(a3)^5=243 鍥犱负a1a5=锛坅1锛²路q^4=锛坅3锛²a2a4=锛坅1锛²路q^4=锛坅3锛²

绛夋瘮鏁板垪an涓,鑻3=3,a9=75姹俛12=,,,鎬
绛旓細a9/a3=q^6=75/3=25;鈭磓^3=卤5;鈭碼12=a9脳q^3=卤375;濡傛灉鏈鏈変粈涔堜笉鏄庣櫧鍙互杩介棶锛屽鏋滄弧鎰忚寰楅噰绾 濡傛灉鏈夊叾浠栭棶棰樿閲囩撼鏈鍚庡彟鍙戠偣鍑诲悜鎴戞眰鍔╋紝绛旈涓嶆槗锛岃璋呰В锛岃阿璋傜瀛︿範杩涙

鍦绛夋瘮鏁板垪{an}涓,鑻3=3,a9=75,鍒檃10=?
绛旓細a9/a3=q^6=25 鎵浠=卤5鐨勭珛鏂规牴 鎵浠10=a9*q=卤75*5鐨勭珛鏂规牴

绛夋瘮鏁板垪{an}涓,鑻3=3,a7=6鍒檃11=?
绛旓細(a7)^2=a3*a11 6^2=3*a11 3a11=36 a11=12

鍦绛夋瘮鏁板垪{an}涓,a3=3,a6=9,鍒檃9=()
绛旓細鍦绛夋瘮鏁板垪锝沘n锝濅腑锛宎3锛3锛宎6锛9锛屽垯a9锛濓紙27 锛塧3=3 a6=a3q^3 9=a3q^3 9=3q^3 q^3=3 a9=a6q^3=9脳3=27

鍦绛夋瘮鏁板垪{an}涓,a3=3,a6=6,鍒檃9=
绛旓細璇烽噰绾

...甯垜瑙ｆ瀽涓嬨傚湪绛夋瘮鏁板垪{An}涓,鑻3=3,a9=75 鍒檃
绛旓細鍥炵瓟锛氬湪绛夋瘮鏁板垪an涓:a3*a15=a9² 鎵浠,a15=a9²/a3=1875 绁濅綘寮蹇!甯屾湜鑳藉府鍒颁綘,濡傛灉涓嶆噦,璇疯拷闂,绁濆涔犺繘姝!O(鈭鈭)O

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