已知弧长和弦长求半径弧长412.81弦长410求半径弧长309.69弦长308.5求半径弧长308.14弦长306求半径

已知弧长C和弦长L求半径R
Rn+1=(1+(L-2*Rn*SIN(C/(2*Rn)))/(L-C*COS(C/(2*Rn))))*Rn
弧长C=412.81弦长L=410求半径
R0=1000
R1=1019.31
R2=1020.29
R3=1020.29
弧长C=309.69弦长L=308.5求半径
R0=1000
R1=1018.32
R2=1019.2
R3=1019.2
弧长C=308.14弦长L=306求半径
R0=500
R1=609.64
R2=699.68
R3=745.11
R4=753.72
R5=753.97
R6=753.97