求弧长,谢谢H=3,L=8,半径=R先求RR^2=(R-H)^2+(L/2)^2R^2=R^2-2RH+H^2-L^2/4R=H/2+L^2/(8*H)R=3/2+8^2/(8*3)R=1.5+64/24R=4.17用反正切再求角度Ntan N=(L/2)/RN=(8/2)/4.17=0.96N=43.83度43.83*2=87.66度求弧长L=N*PI*R/180L=87.66*3.14*4.17/180=
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求弧长,谢谢H=3,L=8,半径=R先求RR^2=(R-H)^2+(L/2)^2R^2=R^2-2RH+H^2-L^2/4R=H/2+L^2/(8*H)R=3/2+8^2/(8*3)R=1.5+64/24R=4.17用反正切再求角度Ntan N=(L/2)/RN=(8/2)/4.17=0.96N=43.83度43.83*2=87.66度求弧长L=N*PI*R/180L=87.66*3.14*4.17/180=
求弧长,谢谢
H=3,L=8,半径=R
先求R
R^2=(R-H)^2+(L/2)^2
R^2=R^2-2RH+H^2-L^2/4
R=H/2+L^2/(8*H)
R=3/2+8^2/(8*3)
R=1.5+64/24
R=4.17
用反正切再求角度N
tan N=(L/2)/R
N=(8/2)/4.17=0.96
N=43.83度
43.83*2=87.66度
求弧长L=N*PI*R/180
L=87.66*3.14*4.17/180=6.37
哪里错了.为什么呢?
求角度的那一步我不会方法是在网上找的,用计算器算的,是不是这一步错了?
求弧长,谢谢H=3,L=8,半径=R先求RR^2=(R-H)^2+(L/2)^2R^2=R^2-2RH+H^2-L^2/4R=H/2+L^2/(8*H)R=3/2+8^2/(8*3)R=1.5+64/24R=4.17用反正切再求角度Ntan N=(L/2)/RN=(8/2)/4.17=0.96N=43.83度43.83*2=87.66度求弧长L=N*PI*R/180L=87.66*3.14*4.17/180=
L=8,H=3,求弧长C?
弧半径为R,弧所对的圆心角为A.
R^2=(R-H)^2+(L/2)^2
R^2=R^2-2*R*H+H^2+L^2/4
2*R*H=H^2+L^2/4
R=H/2+L^2/(8*H)
=3/2+8^2/(8*3)
=4.1667
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((8/2)/4.1667)
=147.48度
C=π*R*A/180=π*4.1667*147.48/180=10.725
tanN不等于(L/2)/R,应该=(L/2)/(R-H)