2012年全国高考数学(理)解答题详解.pdf

淇℃伅绉戝涓庢妧鏈闄 鐢靛瓙宸ョ▼涓庝俊鎭瀛︾郴 鏅矾鍚 鈭嗧按戆淀岸 鐨勫唴瑙扐 銆丅銆丆 鐨勫杈瑰垎鍒负a銆乥 銆乧锛 宸茬煡cos 戆 鈭 戆 + cos 戆 = 1锛岎€亷 = 2饊亹锛 姹 戆? 瑙ｏ細灏嗧暗 = 饊寢 鈭 戆 鈭 戆 浠ｅ叆 cos 戆 鈭 戆 + cos 戆 = 1 cos 戆 鈭 戆 + cos 饊寢 鈭 戆 鈭 戆 = 1 cos 戆 鈭 戆 鈭 cos 戆 + 戆 = 1 cos 戆 cos 戆 + sin 戆 sin 戆 鈭 cos 戆 cos 戆 + sin 戆 sin 戆 = 1 鍖栫畝锛 sin 戆 sin 戆 = 1 鈶 2 鐢别€亷 = 2饊亹 C 涓洪攼瑙 姝ｅ鸡瀹氱悊锛歴in 戆 = 2 sin 戆 鈶 鎶娾憽浠ｅ叆鈶犲緱 2 sin 戆 sin 戆 = 1 2 瑙ｅ緱sin 戆 = 1 鈭 戆 = 饊寢 2 6 濡傚浘锛屽洓妫遍敟肀 鈭 戆错暗戆俄胺 涓紝搴曢潰戆错暗戆俄胺 涓鸿彵褰紝 肀冺按 鈯 搴曢潰 戆错暗戆俄胺 锛岉按戆 锛? 2锛岉眱戆 = 2锛岉案 鏄 肀冺岸 涓婄殑涓€鐐癸紝肀冺案 锛?戆疙岸. (I) 璇佹槑锛氻眱戆 鈯 骞抽潰 戆淀案戆 (II) 璁句簩闈㈣戆 鈭 肀冺暗 鈭 戆 涓 90掳锛屾眰 肀冺胺 涓庡钩闈 肀冺暗戆 鎵€鎴愯鐨勫ぇ灏 (I) 璇佹槑锛 鈭 鍥涜竟褰 戆错暗戆俄胺 鏄彵褰 鈭 戆淀胺 鈯 戆错岸 鈭 肀冺按 鈯 搴曢潰 戆错暗戆俄胺 鈭 肀冺按 鈯 戆淀胺 鈭 戆淀胺 鈯 骞抽潰 肀冺按戆 鈭 戆淀胺 鈯 肀冺岸 璁続BCD 鐨勪腑蹇冧负F锛屽湪涓夎褰AC 涓 戆 戆错岸 戆错岸 6 鐢别€亹肀滍睜鈭犿眱戆俄按 = = = 饊亙戆 戆错岸2 +饊亙戆? 3 P 戆疙岸 6 戆错岸 E 鍦ㄢ垎戆疙岸戆 涓紝 = = 锛屸埓 鈭嗧案戆俄肮 鈭解垎戆错岸肀 鈭 戆疙肮 鈯 肀冺岸 戆俄肮 3 肀冺岸 C F A 缁间笂锛岉眱戆 鈯 骞抽潰 戆淀案戆 濡傚浘锛屽洓妫遍敟肀 鈭 戆错暗戆俄胺 涓紝搴曢潰戆错暗戆俄胺 涓鸿彵褰紝 肀冺按 鈯 搴曢潰 戆错暗戆俄胺 锛岉按戆 锛? 2锛岉眱戆 = 2锛岉案 鏄 肀冺岸 涓婄殑涓€鐐癸紝肀冺案 锛?戆疙岸. (I) 璇佹槑锛氻眱戆 鈯 骞抽潰 戆淀案戆 (II) 璁句簩闈㈣戆 鈭 肀冺暗 鈭 戆 涓 90掳锛屾眰 肀冺胺 涓庡钩闈 肀冺暗戆 鎵€鎴愯鐨勫ぇ灏 (II)瑙ｏ細鍦ㄥ钩闈AB 鍐呰繃鐐笰 浣 AG 鈯 PB锛孏 涓哄瀭瓒 G 鈭典簩闈㈣A 鈭 PB 鈭 C 涓 90掳锛屸埓 骞抽潰 PAB 鈯 骞抽潰 PBC 骞抽潰PAB 鈭 骞抽潰 PBC = PB锛屾晠 AG 鈯 骞抽潰 PBC锛孉G 鈯 BC 戆 鍙堚埖 BC 鈯 PA锛屸埓 BC 鈯ュ钩闈AB锛