数量等8指令
春芽
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如果以O点为坐标原点,OB为x轴,则
A点坐标为A[rcos(wt),rsin(wt)]
rsin(wt)=lsin∠ABO
sin∠ABO=rsin(wt)/l
(cos∠ABO)^2=1-(sin∠ABO)^2=1-[rsin(wt)/l]^2
cos∠ABO=[x-rcos(wt)]/l
{[x-rcos(wt)]/l}^2=1-[rsin(wt)/l]^2
因为l>2r,所以OB>r,x-rcos(wt)>0
[x-rcos(wt)]/l=√{1-[rsin(wt)/l]^2}
x=√{1-[rsin(wt)/l]^2}+rcos(wt)
1年前
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