应用三阶泰勒公式计算sin18的值，怎么求？？？？ 应用三阶泰勒公式计算sin18的值，怎么求
\u5e94\u7528\u4e09\u9636\u6cf0\u52d2\u516c\u5f0f\u8ba1\u7b97sin18\u7684\u503c\uff0c\u600e\u4e48\u6c42\u53ef\u4ee5\u8003\u8651\u6cf0\u52d2\u516c\u5f0f\uff0c\u7b54\u6848\u5982\u56fe\u6240\u793a
sinx≈x-x^3/6
sin18°=sin(π/10)
≈ π/10-π^3/6000
≈0.309
用泰勒公式，把18°带进去
绛旓細cos36搴=sin54搴 浠=sin18搴︼紝鍒╃敤2鍊嶈鍜3鍊嶈鍏紡 1-2x^2=3x-4x^3 鍒嗚В鍥犲紡寰(x-1)(4x^2+2x-1)=0 鏄剧劧0<x<1,4x^2+2x-1=0,x=(鈭5-1)/4 (x=-(鈭5+1)/4鑸嶅幓锛夋墍浠in18搴=(鈭5-1)/4
绛旓細闇瑕佺敤鍒颁笁鍊嶈鍏紡 cos54掳=sin36掳 4cos³18掳-3cos18掳=2sin18掳cos18掳 鍚岄櫎浠os18掳 4cos²18掳-3=2sin18掳 4(1-sin²18掳)-3=2sin18掳 鎵浠 4sin²18掳+2sin18掳+1=0 瑙ｆ柟绋嬶紝sin18掳=(-1+鈭5)/4,(鑸嶈礋)...
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