If `A(at^2,2at)`,`B(a/t^2,-2a/t)` and `C(a,0)` then 2a is equal to. (a) Arithmatic mean of CA and CB (b) Geometric mean of CA and CB (c) Harmonic mean of CA and CB (d) None of these

If D=|(a^(2)+1,ab,ac),(ba,b^(2)+1,bc),(ca,cb,c^(2)+1)| then D equal to

If a, b and c are the arithmetic mean, geometric mean and harmonic mean of two distinct terms respectively, then b^(2) is equal to _______.

P and Q are the mid point of the sides CA and CB respectively of a triangle ABC, right angled at C. then, find the value of 4 (AQ^(2) + BP^(2) ) .

If a,b,c are first three terms of a G.P.If the harmonic mean of a and b is 20 and arithmetic mean of b&c is 5, then no term of this G.P.is square of an integer arithmetic mean of a,b,c is 5 c.b=+-6 d.common ratio of this G.P.is 2

If A is an orthogonal matrix then A^(-1) equals A^(T) b.A c.A^(2) d.none of these