`r gt s`
`{:("Quantity A","Quantity B"),((r+s)(r-s),(s+r)(s-r)):}`

In DeltaABC,r_1/((s-b)(s-c))=

Show that r r_1 =( s -b) (s-c)

If S_(r) denotes the sum of the first r terms of an A.P.then show that (S_(3r)-S_(r-1))/(S_(2r)-S_(2r-1)) is equals

The negative of -s vv(-s^^r) is equaivanlent to :(a)s vv(r vv sim s)(b)s^^r(c)s^^-r(d)s^^(r^^-s)

Prove that ""^(n)C_(r ) ""^(r ) C_(s)= ""^(n)C_(s) ""^(n-s)C_(r-s)