https://s0.wp.com/latex.php?latex=K_%7B%7Bp%7D%7D%3D%5Cleft+%28%5Ccos%28%5Cphi%2B%5Ctheta%29%5Cright+%29%5E%7B2%7D%5Cleft+%28%5Ccos%28%5Ctheta%29%5Cright%29%5E%7B-2%7D%5Cleft+%28%5Ccos%28%5Ctheta-%5Cdelta%29%5Cright+%29%5E%7B-1%7D%5Cleft+%281-%5Csqrt+%7B%7B%5Cfrac+%7B%5Csin%28%5Cphi%2B%5Cdelta%29%5Csin%28%5Cphi%2B%5Cbeta%29%7D%7B%5Ccos%28%5Ctheta-%5Cdelta%29%5Ccos%28%5Ctheta-%5Cbeta%29%7D%7D%7D%5Cright+%29%5E%7B-2%7D+&bg=ffffff&fg=777777&s=0&c=20201002