If `a,b,c` are in H.P and `ab+bc+ca=15` then `ca=`

If a,b,c are in A .P and a^(2),b^(2),c^(2) are in H.P ,then b^(2) = (A) (ca)/(2) (B) 2ca (C) -(ca)/(2) (D) -2ca

Q.If a,b,c are in AP,then bc,ca,ab are in ?

If a,b,c are in A.P then a+1/(bc), b+1/(ca), c+1/(ab) are in

If a,b,c are in A.P., then (bc)/(ca+ab),(ca)/(bc+ab),(ab)/(bc+ca)

If a,b,c are in A.P. prove that: (i) (ab)^(-1),(ca)^(-1) and (bc)^(-1) are also in A.P. (ii) (ab+ac)/(bc),(bc+ca)/(ca),(ca+cb)/(ab) are also in A.P.

If a, b, c are in H.P., prove that, (1)/(bc), (1)/(ca), (1)/(ab) are in H.P.

If a,b,c are in A.P then a+(1)/(bc),b+(1)/(ca),c+(1)/(ab) are in