已知sino+coso=1/3,求sin2o= 理工学科是什么
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很高兴为您解答有用请采纳
sinθ+cosθ=1/3
那么（sinθ+cosθ）∧2=（1/3）∧2=1/9 ①
（sinθ+cosθ）∧2=sinθ∧2+cosθ∧2+2sinθcosθ
由于sinθ∧2+cosθ∧2=1
故（sinθ+cosθ）∧2=1+2sinθcosθ ②
由①可知（sinθ+cosθ）∧2=1/9
将①带入②中，即
1+2sinθcosθ=1/9
所以2sinθcosθ=-8/9
sin2θ=2sinθcosθ=-8/9
绛旓細(sinO-cscO)(cosO-secO)=1/(tanO+cotO)浣犳庝箞璇佹槑鏈夌偣鐪嬪緱鏅,鐪嬫垜鎬庝箞璇 宸=(sinO-cscO)(cosO-secO)=(sin0-1/sin0)(cos0-1/cos0)=sin0cos0-sin0/cos0-cos0/sin0+1/sin0cos0 鍒嗗紑璇-sin0/cos0-cos0/sin0鍚堝苟瀹屾槸-2/sin20 =sin0cos0-2/sin20+2/sin20=sin0cos0 鎶婂垎姣1...
绛旓細1 寮忓瓙灞曞紑鏁寸悊寰 浠(x)=(1+sinO+cosO)x^2-(1+2sinO)x+sinO 棣栧厛婊¤冻 f(0)=sinO>0 f(1)=cosO>0 瀵圭О杞磝=(1+2sinO)/2(1+sinO+cosO)鈭圼0,1]鎵浠ュ彲浠ュ埄鐢ㄢ柍鍒ゅ埆寮忔潵鍒ゆ柇 鍐嶁柍=锛1+2sinO)^2-4sinO(1+sinO+cosO)=1-4sinOcosO<0 鍦ㄧ粨鍚坰inO>0,cosO>0 寰楀埌O鈭(2k蟺+...
绛旓細1銆佷笁瑙掑嚱鏁版槸瑙掑害瀵瑰簲浠绘剰涓よ竟鐨勬瘮鍊间负鍥犲彉閲忕殑鍑芥暟鍙笁瑙掑嚱鏁帮紝涓夎鍑芥暟灏嗙洿瑙掍笁瑙掑舰鐨勫唴瑙掑拰瀹冪殑涓や釜杈归暱搴︾殑姣斿肩浉鍏宠仈锛屼篃鍙互绛変环鍦扮敤涓庡崟浣嶅渾鏈夊叧鐨勫悇绉嶇嚎娈电殑闀垮害鏉ュ畾涔夈2銆佸父瑙佺殑涓夎鍑芥暟鍖呮嫭姝ｅ鸡鍑芥暟銆佷綑寮﹀嚱鏁板拰姝ｅ垏鍑芥暟銆傚湪鑸捣瀛︺佹祴缁樺銆佸伐绋嬪绛夊叾浠栧绉戜腑锛岃繕浼氱敤鍒板浣欏垏鍑芥暟銆佹鍓插嚱鏁...
绛旓細灏忚涓簅,閭ｄ箞杈冪煭鐨勭洿瑙掕竟涓sino锛岃緝闀跨殑涓篶oso锛屽皬姝ｆ柟褰㈠彉闀1/5 锛屾墍浠oso-sino=1/5 锛1锛夊钩鏂 寰楀埌sin^2o+cos^2o-2sino*coso =1/25 锛2锛夊緱鍒 coso*sino=12/25 锛3锛夛紙2锛+4*锛3锛 寰楀埌(sino+coso)^2 =49/25 sino coso閮芥槸姝ｆ暟 鎵浠 sino+coso=7/5 锛4锛夛紙1锛*锛...
绛旓細鐩寸嚎鏂瑰悜鍚戦噺鍜屽钩闈㈢殑娉曞悜閲忕殑 澶硅鐢ㄤ綑寮﹁绠楋紝鐢辫繖涓鍜岀洿绾垮拰骞抽潰鎵鎴愮殑瑙 浜掍綑锛屽埄鐢ㄨ瀵煎叕寮忓寲涓烘寮︼紝涓鑸攤cos<l,娉曞悜閲>鈹=sin绾块潰瑙掞紝鍒嗘竻瑙掑害锛屾纭浆鍖栥
绛旓細sino+coso=2sina 涓よ竟骞虫柟 sin^2o+2sinocoso+cos^2o=4sin^2a 1+2sin^2B=4sin^2a 1+2(1-cos2B)/2=4(1-cos2a)/2 鏁寸悊寰楀埌 2cos2a=cos2b
绛旓細瑙ｇ瓟锛氳繖绉嶉鐩氨鏄埄鐢ㄥ垏鍖栧鸡锛岀劧鍚庡埄鐢ㄥ嶈鍏紡鍗冲彲銆倀ano+1/tano=4 鍒囧寲寮 sino/coso+1/(sino/coso)=4 sino/coso+coso/sino=4 閫氬垎,寰楀埌 (sin²o+cos²o)/(sinocos0)=4 1/[(1/2)sin2o]=4 2/sino=4 鎵浠 sin2o=1/2 ...
绛旓細y=1+sin2胃=(sin²胃+cos²胃)+2sin胃cos胃=(sin胃+cos胃)²=x²锛寈=sin胃+cos胃=鈭2脳(sin胃cos45掳+cos胃sin45掳)=鈭2sin(胃+45掳)锛屽洜涓何糕垐R锛屾墍浠in胃鈭圼-1,1]锛屾墍浠ユ槸瀹氫箟鍩焫鈭圼-鈭2锛屸垰2]锛寉=x²...
绛旓細锛1锛塧//b sinO=鈭3cosO tanO=鈭3 O鈭(0,蟺/2),O=蟺/3 sinO=鈭3/2,cosA=1/2 (2)f(o)=a²+b²+2ab =1+4+2(鈭3sinO+cosO)=5+4sin(O+蟺/6)sin(o+蟺/6)鈭圼-1,1]鎵浠 f(o)鈭圼-1,9]
绛旓細1 鍨傜洿灏辨槸涓や釜鐩镐箻=0 鍙互姹傚嚭tan 鍐嶆眰sino鍜coso鐨勫 2 鐩存帴鍏堝彉褰 鍚in鎷嗗紑 鐒跺悗鎶妔ino鍜宑oso甯﹀叆 姹傚嚭tanp 鍐嶆牴鎹寖鍥存眰cosp
