Mathematics
If p = xm + n.yl, q = xn + l.ym and r = xl + m.yn, prove that
pm - n.qn - l.rl - m = 1
Answer
Substituting value of p, q and r in pm - n.qn - l.rl - m = 1.
= (xm + n.yl)m - n.(xn + l.ym)n - l.(xl + m.yn)l - m
= x(m + n)(m - n).yl(m - n).x(n + l)(n - l).ym(n - l).x(l + m)(l - m).yn(l - m)
= xm2 - n2.xn2 - l2.xl2 - m2.ylm - ln.ymn - ml.ynl - nm
= xm2 - n2 + n2 - l2 + l2 - m2.ylm - ln + mn - ml + nl - nm
= x0.y0
= 1.1
= 1.
Hence, proved that, pm - n.qn - l.rl - m = 1.