下列命题中正确的是( )A.若a,b,c是等差数列,则log2a,log2b,log2c是等比数列B.若a,b,c是等
\u82e5a,b,c\u662f\u7b49\u6bd4\u6570\u5217,\u5219log2a,log2b,log2c\u662f\u7b49\u5dee\u6570\u5217\u9519\u5728\u54ea\u5bf9\u6570\u51fd\u6570y=logax\u7684\u771f\u6570x\u5fc5\u987b\u5927\u4e8e0
\u5728\u8fd9\u4e2a\u6570\u5217\u4e2d\u6ca1\u6709\u8bf4\u660ea,b,c\u7684\u8303\u56f4
\u6240\u4ee5\uff0c\u9519\u4e86
\u82e5\u6b63\u6570a\uff0cb\uff0cc\u662f\u7b49\u5dee\u6570\u5217\uff0c\u52192a\uff0c2b\uff0c2c\u662f\u7b49\u5dee\u6570\u5217\uff0c\u4f46\u4e0d\u4e00\u5b9a\u662f\u7b49\u6bd4\u6570\u5217\uff0c\u6545A\u9519\u8bef\uff1b\u82e5\u6b63\u6570a\uff0cb\uff0cc\u662f\u7b49\u6bd4\u6570\u5217\uff0c\u52192a\uff0c2b\uff0c2c\u662f\u7b49\u6bd4\u6570\u5217\uff0c\u4f46\u4e0d\u4e00\u5b9a\u662f\u7b49\u5dee\u6570\u5217\uff0c\u6545B\u8bef\uff1b\u82e5\u6b63\u65701\uff0c2\uff0c3\u662f\u7b49\u5dee\u6570\u5217\uff0c\u5219log21=0\u4e0d\u80fd\u505a\u4e3a\u7b49\u6bd4\u6570\u5217\u7684\u9879\uff0c\u6545C\u9519\u8bef\uff1b\u82e5\u6b63\u6570a\uff0cb\uff0cc\u662f\u7b49\u6bd4\u6570\u5217\uff0c2log2b=log2b2=log2\uff08ac\uff09=log2a+log2c\uff0c\u6545log2a\uff0clog2b\uff0clog2c\u6210\u7b49\u5dee\u6570\u5217\uff0c\u6545D\u6b63\u786e\uff1b\u6545\u9009D
对于A,a=b=c=0,结论不成立;对于B,a=-1,b=1,c=-1,结论不成立;
对于C,若a,b,c是等差数列,则2b=a+c,所以2a,2b,2c是等比数列,成立;
对于D,a=-1,b=1,c=-1,则2a,2b,2c是等差数列不成立.
故选:C.
绛旓細瑙o細A銆佸綋涓や釜鏃犵悊鏁颁簰涓虹浉鍙嶆暟鏃讹紝鍜屼负0锛屾晠姝ら夐」閿欒锛汢銆佹鏁扮殑骞虫柟鏍规湁涓や釜锛屾晠姝ら夐」閿欒锛汣銆佸紑绔嬫柟绛変簬瀹冩湰韬殑瀹炴暟鏈1锛岋梗1锛0锛屾晠姝ら夐」閿欒锛汥銆佽礋鏁扮殑绔嬫柟鏍规槸璐熸暟锛屾閫夐」姝g‘锛庢晠閫夛細D锛庣偣璇勶細姝ら涓昏鑰冩煡浜鍛介涓庡畾鐞嗭紝鐔熺粌鎺屾彙鐩稿叧鐨勬硶鍒欐槸瑙i鍏抽敭锛
绛旓細鏍规嵁缁濆鍊肩殑鎬ц川銆佸掓暟鐨勫畾涔夈佺珛鏂规牴鐨勫畾涔夈佺畻鏈钩鏂规牴鐨勫畾涔夛紝寰桝銆侀潪璐熸暟鐨勭粷瀵瑰肩瓑浜庡畠鏈韩锛屾晠閫夐」A閿欒锛汢銆佸掓暟绛変簬瀹冩湰韬殑鏁版槸1锛-1锛屾晠閫夐」B閿欒锛汣銆佺畻鏈钩鏂规牴绛変簬瀹冩湰韬殑鏁版槸0锛1锛屾晠閫夐」C閿欒锛汥銆佺珛鏂规牴绛変簬瀹冩湰韬殑鏁版槸0锛1锛-1锛屾晠閫夐」D姝g‘锛庢晠閫塂锛
绛旓細骞冲垎寮︾殑鐩村緞鍨傜洿浜庡鸡锛屽苟骞冲垎寮︽墍瀵圭殑寮э紝寰堝鏄撻敊璇殑璁や负鏄姝g‘鐨锛屽叾瀹炲瀭寰勫畾鐞嗘槸锛欰銆佹纭紱B銆佲滃钩鍒嗭紙涓嶆槸鐩村緞锛夊鸡鐨勭洿寰勫瀭鐩翠簬寮︼紝骞跺钩鍒嗗鸡鎵瀵圭殑寮р濓紝鍦ㄥ钩鍒嗗鸡鍋氭潯浠舵椂涓瀹氳娉ㄦ剰骞冲垎鐨勬槸涓嶆槸鐩村緞鐨勫鸡鏃讹紝鎵嶈兘鐢卞瀭寰勫畾鐞嗗緱鍑哄瀭鐩翠簬寮﹀苟涓斿钩鍒嗗鸡鎵瀵圭殑寮э紝鏁呴敊璇紱C銆佹病鏈夌粰鍥撅紝A銆丅...
绛旓細D 鑻c锛瀊c锛屼笉绛夊紡涓よ竟鍚屾椂闄や互C锛屽綋C>0鏃讹紝寰a锛瀊锛屽綋C<0鏃讹紝a<b锛屾墍浠A閿欙紱鐢变簬 锛屼絾 锛屾墍浠閫夐」閿欙紱鐢变簬 锛屼絾 涓嶆垚绔嬶紝鎵浠ラ夐」C閿欙紱鐢卞嚱鏁 鏄崟璋冮掑鐨勶紝鑻 ,鍒檃锛渂锛屾晠閫夋嫨D.
绛旓細鏁姝g‘锛涒憿鈭礲²-4ac锛0锛屸埓鎶涚墿绾夸笌x杞存湁涓や釜涓嶅悓鐨勪氦鐐癸紝鈭翠簩娆″嚱鏁皔=ax²+bc+c鐨勫浘璞′笌鍧愭爣杞寸殑鍏叡鐐圭殑涓暟鏄3鎴2锛屾晠姝g‘锛涒懀鈭礲锛瀉+c锛岄偅涔堣b=2锛宎=-4锛宑=-2锛屸埓b²-4ac=4-32锛0锛屸埓涓鍏冧簩娆℃柟绋媋x²+bx+c=0娌℃湁瀹炴暟鏍癸紝鏁呴敊璇紟鏁呴塁锛...
绛旓細閫塀
绛旓細D 璇曢鍒嗘瀽锛氭牴鎹鎰忥紝鐢变簬涓涓鍛介鐨閫嗗懡棰樹负鐪燂紝鍒欏畠鐨勫惁鍛介涓瀹氫负鐪燂紝鍥犳A閿欒锛屽浜嶣锛岀敱浜庘 鈥濅笌鈥 鈥濈瓑浠凤紝鏁呴敊璇紝瀵逛簬C锛岀敱浜庘 ,鍒 鍏ㄤ负 鈥濈殑閫嗗惁鍛介鏄鈥滆嫢 涓嶅叏涓 , 鍒 鈥濇晠閿欒锛屾晠閫塂.鐐硅瘎锛氫富瑕佹槸鑰冩煡浜嗗懡棰樼湡鍋囩殑鍒ゅ畾锛屽睘浜庡熀纭棰樸
绛旓細绛旀鏄細A,D
绛旓細A銆丆涓姝g‘锛屽綋鐐筆鍦ㄥ钩闈㈠唴鏃讹紱B姝g‘锛岃繃绌洪棿浠讳竴鐐筆鏈変笖浠呮湁涓鏉′笌骞抽潰伪鍨傜洿鐨勭洿绾匡紱鏁匘涓嶆纭紟鏁呴塀锛
绛旓細A銆佽嫢鈭燤ON+鈭燦OP=90掳锛屽綋涓涓鍦ㄥ彟涓涓鐨勫閮ㄦ椂锛屸垹MOP涓虹洿瑙掞紝鎵浠閫夐」閿欒锛汢銆佄变笌尾浜掍负琛ヨ锛屽垯伪涓幬插彲鑳介兘涓虹洿瑙掞紝鎵浠閫夐」閿欒锛汣銆佷袱閿愯涔嬪拰鍙兘涓虹洿瑙掞紝涔熷彲鑳戒负閿愯鎴栭挐瑙掞紝鎵浠閫夐」閿欒锛汥銆佽嫢伪涓幬蹭簰涓轰綑瑙掞紝鍒櫸变笌尾鍧囦负閿愯锛屾墍浠閫夐」姝g‘锛庢晠閫塂锛