수식 4: "y" squared equals StartFraction, "B" squared left parenthesis, "L" Superscript, 2 , Baseline minus 4 "x" squared , right parenthesis Over 4 left parenthesis, "L" squared plus 8 "W" "x" plus 4 "W" squared , right parenthesis , EndFractiony2=B2L2−4x24L2+8Wx+4W2