化简cos平方a-sin平方a的结果是?
\u667a\u6167\u4f5c\u4e1a\u7cfb\u7edf-\u667a\u6167\u4f5c\u4e1a\u662f\u4ec0\u4e48-\u8ba9\u6559\u80b2\u4fe1\u606f\u5316 2x+y/3=1x+3y/5=1
所以2x+y=3 (1)
x+3y=5 (2)
(1)×3-(2)
6x+3y-x-3y=9-5
5x=4
x=4/5
y=3-2x=3/5
3（a+1)
绛旓細鍝簺椤瑰湪鍒嗘瘝涓婏紵鍐欏緱寰堜笉娓呮銆備及璁℃槸杩欐牱锛歠锛坸锛=(1+cos2x)锛4sin(蟺锛2+x)-asinx锛2cos(蟺-x锛2)=2[cosx]^2锛廩4cos x ]-asinx锛廩2sin(x/2)]=cosx/2-a cos(x/2)=(2cos^2(x/2)-1]/2-acos(x/2)=u^2 -au-1/2,-1<=u<=1,濡傛灉a>=0,鍏舵渶澶у间负1+a-1/2,...
绛旓細瑕佽瘉锛歝ot骞虫柟a - cos骞虫柟a = cot骞虫柟a*cos骞虫柟a 灏辨槸璇侊細1/cos骞虫柟a-1/cot骞虫柟a = 1 灏辨槸璇侊細1/cos骞虫柟a-sin骞虫柟a/cos骞虫柟a = 1 灏辨槸璇侊細锛1-sin骞虫柟a锛/cos骞虫柟a = 1 鍥犱负锛歴in骞虫柟a+cos骞虫柟a = 1 鎵浠ワ細1-sin骞虫柟a = cos骞虫柟a 鎵浠ワ細锛1-sin骞虫柟a锛/cos骞虫柟a = 1 鏁...
绛旓細濡傛灉鏄 (1+2sinacosa)/(cos^2a - sin^2a) 鍒 瀹= (sin^2a + cos^2a -2sinacosa) /(cos^2a-sin^2a)= (sina-cosa)^2/(cosa-sina)(cosa+sina)= (cosa-sina)/(cosa+sina)= (1-tana)/(1+tana)鑰屾牴鎹叕寮弔an(pi/4-a) = (tanpi/4 - tana)/(1+tanpi/4 tana)= (1-...
绛旓細鍖栫畝寰2sin骞虫柟acos骞虫柟a 鍐嶇湅涓嬮潰锛氫篃鎶婂钩鏂瑰紡鎷嗗紑锛宑os6娆℃柟a+3cos4娆℃柟asin骞虫柟a+3cos骞虫柟asin4娆℃柟a+sin6娆℃柟a-sin6娆℃柟a-cos6娆℃柟a 鍖栫畝寰3cos4娆℃柟asin骞虫柟a+3cos骞虫柟asin4娆℃柟a 涓婁笅鍚屾椂闄や互cos骞虫柟asin骞虫柟a 寰2/锛3sin骞虫柟a+3cos骞虫柟a锛=2/3 ...
绛旓細cos^2(45掳+a)-sin^2(45掳+a)=cos[2(45掳+a)]=cos(90掳+2a)=-sin2a.=-2sinacosa
绛旓細鍘熷紡=(1/2)[1+cos2伪-(1-cos2尾)]=(1/2)(cos2伪+cos2尾)鍙互鍚楋紵
绛旓細杩欐槸涓夎鎭掔瓑寮忥紙Trigonometric Identity锛変箣涓锛岃〃绀烘寮﹁ $a$ 鐨骞虫柟鍔犱笂浣欏鸡瑙 $a$ 鐨勫钩鏂圭瓑浜 $1$锛屽嵆锛歕sin^2 a + \cos^2 a = 1 杩欎釜鎭掔瓑寮忎篃琚О涓衡滃嬀鑲″畾鐞嗏濇垨鈥滃崟浣嶅渾涓婁换鎰忎竴鐐瑰埌鍦嗗績鐨勮窛绂诲钩鏂圭瓑浜庡叾妯潗鏍囧钩鏂逛笌绾靛潗鏍囧钩鏂圭殑鍜屸濄
绛旓細cos(A+B)=cosAcosB-sinAsianB cos(A-B)=cosAcosB+sinAsinB 鐩镐箻鍚庡皢cos锛骞虫柟锛塀鐢紙1-sin锛堝钩鏂癸級B锛変唬,sin锛堝钩鏂癸級A鐢紙1-cos锛堝钩鏂癸級A锛変唬,鍖栫畝灏卞彲浠ヤ簡
绛旓細cos锛埼+尾锛=cos尾cos伪-sin尾sin伪 sin锛埼+尾锛=sin伪cos尾+cos伪sin尾 sin锛埼-尾锛=sin伪cos尾-cos伪sin尾 tan锛埼+尾锛=锛 tan伪+tan尾锛/锛1-tan伪tan尾锛=tan伪+tan尾+ tan锛埼+尾锛* tan伪tan尾 tan锛埼-尾锛=锛 tan伪-tan尾锛/锛1+ tan伪tan尾锛...
绛旓細鍊熺敤浣犵殑琛ㄨ揪鏂规硶灏辨槸锛(cosa)骞虫柟鍒嗕箣(sina)骞虫柟绛変簬(tana)鐨勫钩鏂广傝瑙佸涓嬫帹绠楁埅鍥撅細濡傛灉瑙ｅ喅浜嗛棶棰橈紝娆㈣繋浣犵偣鍑 鈥滈噰绾斥濄傚鏋滀粛鏈変笉鏄庯紝娆㈣繋杩介棶銆
