定积分，这步是怎么来的，1/10是怎么来的
\u9ad8\u6570\u5b9a\u79ef\u5206\uff0c\u6c42\u89e3\u8fd9\u4e00\u6b65\u600e\u4e48\u6765\u7684\u5199\u8fd9\u4e66\u7684\u4eba\u597d\u61d2\uff0c\u7701\u4e86\u597d\u591a\u6b65\u9aa4
\u9996\u5148\uff0c\u5728\u4e00\u4e2a\u5468\u671f\u5185\uff0csin\u6216\u8005cos\u7684\u79ef\u5206\u662f0\uff0c\u6240\u4ee5-2cost\u7684\u79ef\u5206\u662f0\uff0c\u76f4\u63a5\u53bb\u6389
\u5269\u4e0b\u90a3\u6b65\u9aa4\u5c31\u7701\u592a\u591a\u4e86
\uff08cost\uff09^2\u7684\u5468\u671f\u662fpi/2\u5207\u90fd\u662f\u5927\u4e8e\u7b49\u4e8e0\u7684\u7136\u540e\u76f4\u63a5\u628a\u4e0a\u9650\u4fee\u6539\u4e86\uff0c\u8ba1\u7b97\u4e00\u4e2a\u5468\u671f\u7684
\u8c22\u8c22\u91c7\u7eb3
cos2u=(cosu)^2-(sinu)^2=2(cosu)^2-1
(cosu)^2=1/2(1+cos2u)
绛旓細涓涓嚱鏁帮紝鍙互瀛樺湪涓瀹氱Н鍒嗭紝鑰屼笉瀛樺湪瀹氱Н鍒嗭紱涔熷彲浠ュ瓨鍦ㄥ畾绉垎锛岃屼笉瀛樺湪涓嶅畾绉垎銆備竴涓繛缁嚱鏁帮紝涓瀹氬瓨鍦ㄥ畾绉垎鍜屼笉瀹氱Н鍒嗭紱鑻ュ彧鏈夋湁闄愪釜闂存柇鐐癸紝鍒欏畾绉垎瀛樺湪锛涜嫢鏈夎烦璺冮棿鏂偣锛屽垯鍘熷嚱鏁颁竴瀹氫笉瀛樺湪锛屽嵆涓嶅畾绉垎涓瀹氫笉瀛樺湪銆傞粠鏇肩Н鍒嗕粙缁嶏細瀹氱Н鍒嗙殑姝ｅ紡鍚嶇О鏄粠鏇肩Н鍒嗐傜敤榛庢浖鑷繁鐨勮瘽鏉ヨ锛屽氨鏄妸...
绛旓細b銆戝垎鎴恘浠斤紝鐢ㄥ钩琛屼簬y杞寸殑鐩寸嚎鎶婂叾鍒嗗壊鎴愭棤鏁颁釜鐭╁舰锛屽啀姹傚綋n鈫+鈭炴椂鎵鏈夎繖浜涚煩褰㈤潰绉殑鍜屻涓涓瀹氱Н鍒寮忕殑鍊硷紝灏辨槸鍘熷嚱鏁板湪涓婇檺鐨勫间笌鍘熷嚱鏁板湪涓嬮檺鐨勫肩殑宸傛彮绀轰簡绉垎涓庨粠鏇肩Н鍒嗘湰璐ㄧ殑鑱旂郴锛屽彲瑙佸叾鍦ㄥ井绉垎瀛︿互鑷虫洿楂樼瓑鐨勬暟瀛︿笂鐨勯噸瑕佸湴浣嶏紝鍥犳锛岀墰椤-鑾卞竷灏煎吂鍏紡涔熻绉颁綔寰Н鍒嗗熀鏈畾鐞嗐
绛旓細鍒╃敤琚Н鍑芥暟鐨勫绉版э紝濂囧嚱鏁板绉板尯闂绉垎涓洪浂锛屽伓鍑芥暟瀵圭О鍖洪棿绉垎涓哄崟渚х殑2鍊嶃
绛旓細鈭2u/(1+u)du=2鈭(1+u-1)/(1+u)du =2鈭1-1/(1+u)du=2u-2ln|1+u|+C
绛旓細椹簯鏇惧湪鈥滃叏鐞冨コ鎬у垱涓氳呭ぇ浼氣濅笂璁插埌锛氣滃コ鎬у笇鏈涙妸寮蹇冦佸揩涔愩佺編濂界殑浜嬫儏甯︾粰鍒汉锛岃繖浜涘搧璐ㄨ涓栫晫鏇寸編濂姐佽鍒汉鏇村揩涔锛岃繖鎵嶆槸鍋氫紒涓氭垚鍔熺殑蹇呭鏉′欢銆備綘涓嶇涔愭剰涓嶄箰鎰忥紝鍠滄涓嶅枩娆紝鎺ュ彈涓嶆帴鍙楋紝30骞翠互鍐咃紝鍙﹀涓绉嶁樿冭檻浠栦汉銆佹敞閲嶄綋楠屻佸埄浠栦富涔夆欑殑濂虫ф濈淮锛屽皢浼氭垚涓烘湭鏉30骞翠富娴佷腑鐨勪富娴侊紱涓栫晫...
绛旓細鈭(a,x)f(x)dt =f(x)鈭(a,x)dt, 娉細杩欏効鍙橀噺鏄痶锛宖(x)鏄父鏁 =f(x)(x-a)
绛旓細鏍规嵁绉垎鍏紡
绛旓細濡傚浘
绛旓細褰搙=蟺鏃讹紝u=0 褰搙=0鏃讹紝u=蟺 鈭(0鈫捪)xf(sinx)dx =鈭(蟺鈫0)(蟺-u)f[sin(蟺-u)]*(-du)=鈭(0鈫捪)(蟺-u)f[sin(蟺-u)]du =鈭(0鈫捪)蟺f[sin(蟺-u)]du-鈭(0鈫捪)uf[sin(蟺-u)]du =蟺鈭(0鈫捪)f(sinu)du-鈭(0鈫捪)uf(sinu)du (瀹氱Н鍒涓庣Н鍒嗗彉閲忓瓧姣嶆棤...
绛旓細搴旂敤浜涓涓叕寮忥紝褰 x锛0 鏃 arctanx+arctan(1/x)=蟺/2
