数学：cos100度=k，则tan80度=多少 1.cos100度=k 则，sin(-80度)=？ tan(...

cos(-80\u5ea6\uff09=k\uff0c\u90a3\u4e48tan100\u5ea6=\uff1f\u8be6\u7ec6\u89e3\u7b54\uff0c\u5305\u62ec\u8fd0\u7528\u77e5\u8bc6\u70b9\u4e0e\u516c\u5f0f\u3002

sin100 = sin (180 - 80) = sin80 ; // \u6839\u636esin\u7684\u51fd\u6570\u56fe\u50cf\u5f97\u6765\u7684\u5173\u7cfb\u5f0f\uff0c\u6559\u6750\u91cc\u5e94\u8be5\u4f1a\u5199\u3002
cos100 = cos(180 - 80) = -cos80 ; // \u540c\u7406\u3002
cos(-80) = cos 80 = k, -cos80 = -k; //\u540c\u7406\u3002
sin 80 = \u6839\u53f7\u4e0b1 - (cos 80)^2 = \u6839\u53f7\u4e0b1-k^2; // \u6839\u636e\u516c\u5f0f(sin \u03b1)^2 + (cos \u03b1)^2 = 1\u3002
tan100 = sin100 / cos100 = sin 80 / (-cos 80) = - (\u6839\u53f7\u4e0b1-k^2) / k;

1\u3001\u56e0\u4e3acos100º\uff1dk\uff0c
\u6240\u4ee5sin100º\uff1d\u221a(1-k²)\uff0c
\u56e0\u6b64 sin(-80º)\uff1d-sin100º\uff1d- \u221a(1-k²)\uff0c
tan(-260º)\uff1dtan100º\uff1dk/\u221a(1-k²)\u3002
2\u3001\u56e0\u4e3asin(-160º)\uff1dk\uff0c
\u6240\u4ee5 cos(-160º)\uff1d- \u221a(1-k²)\uff0c
\u56e0\u6b64cos340º\uff1d-cos(-160º)\uff1d\u221a(1-k²)\uff0c
tan970º\uff1d1/tan20º\uff1d-1/tan(-160º)
\uff1d- \u221a(1-k²) / k \u3002

cos100°=k
cos80°=cos(180°-100°）=-cos100°=-k
sin²80°=1-cos²80°=1-k²
sin80°>0
sin80°=√(1-k²）
tan80°=sin80°/cos80°=-√(1-k²)/k

楂樹竴鏁板棰 璁cos100搴=k,鍒檛g80搴︾殑鍊兼槸澶氬皯? 鍛婅瘔鎴戣缁嗚繃绋...
绛旓細100搴鍦ㄧ浜岃薄闄,姝ゆ椂sin鍊间负姝 鎵浠ョ敱cos100=k锛泂in100^2+cos100^2=1 寰梥in100=鈭1-k^2 鎵浠an100=sin100/cos100=锛堚垰1-k^2锛/k 鏍规嵁璇卞鍏紡锛歵an(180-100)=-tan100=tan80 鎵浠an80=-锛堚垰1-k^2锛/k

鏁板:cos100搴=k,鍒檛an80搴=澶氬皯
绛旓細cos80掳=cos(180掳-100掳锛=-cos100掳=-k sin²80掳=1-cos²80掳=1-k²sin80掳>0 sin80掳=鈭(1-k²锛塼an80掳=sin80掳/cos80掳=-鈭(1-k²)/k

鑻ユ槸cos(100搴)=k.鍒檛an(鈥80)搴︾瓑浜庡灏
绛旓細tan锛-80掳锛=-tan80掳 =-tan锛180掳-100掳锛=tan100掳 =鏍瑰彿锛1-k²锛/k 婊℃剰璇峰強鏃堕噰绾

1.cos100搴=k 鍒,sin(-80搴)=? tan(-260搴)=? 2.sin(-160
绛旓細1銆佸洜涓cos100º锛漦锛鎵浠in100º锛濃垰(1-k²)锛屽洜姝 sin(-80º)锛-sin100º锛- 鈭(1-k²)锛宼an(-260º)锛漷an100º锛漦/鈭(1-k²)銆2銆佸洜涓簊in(-160º)锛漦锛屾墍浠 cos(-160º)锛- 鈭(1-k²)锛屽洜姝os340º...

璁COS100搴绛変簬K,tan80鏄?
绛旓細sin100搴=鈭(1-k�0�5)锛宼an80搴=-tan100搴=-[鈭(1-k�0�5)]/k

鏁板瑙掑害鍒堕棶棰,姹傝В
绛旓細浠绘剰瑙掗兘鎴愮珛鐨勩傚洜涓 cos100掳=k k灏辨槸璐熸暟锛宑os80掳=-k鏄鏁般

璁＄畻cos100搴鐨勫,缁撴灉鏄?
绛旓細cos100=cos(32蟺-0.5312)=cos0.5312 =cos(0.5312脳180掳/3,1416)=cos30.43掳 鈭碿os31掳<cos100<cos30掳=鈭3/2.

cos(-80搴)=k,tan100搴=?
绛旓細- 80) = -cos80 ; // 鍚岀悊銆俢os(-80) = cos 80 = k, -cos80 = -k; //鍚岀悊銆俿in 80 = 鏍瑰彿涓1 - (cos 80)^2 = 鏍瑰彿涓1-k^2; // 鏍规嵁鍏紡(sin 伪)^2 + (cos 伪)^2 = 1銆倀an100 = sin100 / cos100 = sin 80 / (-cos 80) = - (鏍瑰彿涓1-k^2) / k;

鍙戠幇涓嶆噦鏁板棰,鏈涘悇浣嶆暟瀛﹀ぉ鎵嶅府蹇檦~(鎬)
绛旓細tan100=tan(90+10)=-cot10=K,cot10=-K,sin80=sin(90-10)=cos10---璁句负x cot10=cos10/sin10 -k=x/(1-x^2)^(1/2)涓よ竟骞虫柟锛岃В鍑簒鍗充负鎵姹傘傛敞鎰忥細10搴﹀湪绗竴璞￠檺锛屾晠cot10>0,cos10>0,sin10>0锛屾樉鐒讹細k<0

楂樹腑涓夎鍑芥暟 璁COS(-80搴)=K,閭ｄ箞tan100搴=澶氬皯\x0c杩囩▼瑕佽缁哶鐧惧害鐭 ...
绛旓細cos(-80)=cos80=-cos100=k,cos100=-k sin100=鏍瑰彿锛1-k^2)tan100=sin100/cos100=-鏍瑰彿锛1-k^2)/k

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