19/04/27 14:58:17.93 LILOzJjY.net
前>>576
△PKA^2=-4(2r^2-2r-1)sin^2θ+sinθ√[{16(4r^4-8r^3+4r+1)+4r^4-8r^3+4r^2})sin^2θ-(1-2r+2r^2)^2]
=-4(2r^2-2r-1)sin^2θ+sinθ√[{68r^4-136r^3+4r^2+64r+16}sin^2θ-(1-2r+2r^2)^2]
∴△PKA=√〔sinθ√[{68r^4-136r^3+4r^2+64r+16}sin^2θ-(1-2r+2r^2)^2]-4(2r^2-2r-1)sin^2θ〕
できたできた!!