If `a,b,c in R^+` then `bc/(b+c) +ac/(a+c)+ab/(a+b)` is always

If a,b,c are in proportion,then a^(2)=bc(b)b^(2)=ac(c)c^(2)=ab(d) None of these

in a triangle ABC , (b+c) ( bc ) cos A + (a +c) (ac) cos B + ( a+b) (ab) cos C Is

If a:b=2:3 and b:c=5:7 then find a:c and a:b:c

Sum of a – b + ab, b + c – bc and c – a – ac is

If a:b=4:5 and b:c=2:3, then a:c=

If bc + ab + ca = abc, then the value of (b+c)/(bc(1-a))+(a+c)/(ac(1-b))+(a+b)/(ab(1-c)) is

If a,b,c are there given non-coplanar vectors and any arbitrary vector r is in space. Where, Delta_(1) =|{:(r.a,b.a,c.a),(r.b,b.b,a.b),(r.a,b.c,c.c):}|, Delta_(2)=|{:(a.a,r.a,c.a),(a.b,r.b,c.b),(a.c,r.c,c.c):}|, Delta_(3) =|{:(a.a,b.a,r.a),(a.b,b.b,r.b),(a.c,b.c,r.c):}|, Delta=|{:(a.a,b.a,c.a),(a.b,b.b,c.b),(a.c,c.c,c.c):}| The value of |{:(a,b,c),(a.p,b.p,c.p),(a.q,b.q,c.q):}| is: