If `a, b, c and d` are in harmonic progression, then `(1)/(a), (1)/(b), (1)/(c) and (1)/(d)` are in ______ progression.

If a, b and c are in geometric progression then, a^(2), b^(2) and c^(2) are in ____ progression.

In Delta ABC, sec A, sec B, sec C are in harmonic progression, then

If a,b,c are in geometric progression then ((1)/(b)+ (1)/(c )-(1)/(a)) ((1)/(c ) + (1)/(a) - (1)/(b)) = ……..

If 1 , a, b and 4 are in harmonic progression , then the value of a + b is equal to

If 1 , a, b and 4 are in harmonic progression , then the value of a + b is equal to

If a, b and c are positive numbers in arithmetic progression and a^(2), b^(2) and c^(2) are in geometric progression, then a^(3), b^(3) and c^(3) are in (A) arithmetic progression. (B) geometric progression. (C) harmonic progression.

If (1)/(a)+(1)/(b)=(1)/(c)+(1)/(d) , express a in terms of b,c and d.

If a, b, c are in geometric progression, then prove that : (1)/(a^(2)-b^(2))+(1)/(b^(2))=(1)/(b^(2)-c^(2))

If a, b, c are in geometric progression, then prove that : (1)/(a^(2)-b^(2))+(1)/(b^(2))=(1)/(b^(2)-c^(2))

Given a, b, c (taken in the order) are in arithmatic progression b, c, d (taken in this order) are in geometric progression and c, d, k (taken in this order) are in Harmonic progression. If a= 2 and k = 18 then possible values of 'c' can be