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=](/uploads/image/z/14609638-46-8.jpg?t=%E6%B1%82%E5%BC%A7%E9%95%BF%2C%E8%B0%A2%E8%B0%A2H%3D3%2CL%3D8%2C%E5%8D%8A%E5%BE%84%3DR%E5%85%88%E6%B1%82RR%5E2%3D%28R-H%29%5E2%2B%28L%2F2%29%5E2R%5E2%3DR%5E2-2RH%2BH%5E2-L%5E2%2F4R%3DH%2F2%2BL%5E2%2F%288%2AH%29R%3D3%2F2%2B8%5E2%2F%288%2A3%29R%3D1.5%2B64%2F24R%3D4.17%E7%94%A8%E5%8F%8D%E6%AD%A3%E5%88%87%E5%86%8D%E6%B1%82%E8%A7%92%E5%BA%A6Ntan+N%3D%28L%2F2%29%2FRN%3D%288%2F2%29%2F4.17%3D0.96N%3D43.83%E5%BA%A643.83%2A2%3D87.66%E5%BA%A6%E6%B1%82%E5%BC%A7%E9%95%BFL%3DN%2API%2AR%2F180L%3D87.66%2A3.14%2A4.17%2F180%3D)
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)