`A_(1)` and `A_(2)` are two ores of metal `M.A_(1)` on calcination gives a black precipitate, `CO_(2)` and water. Identify `A_(1)` and `A_(2)`.
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A_(1) " and " A_(2) are the two ores of a metal M. They undergo the following changes. Identify the orea A_(1) " and " A_(2) . I_(2)+ppt overset("Dil.HCl")underset(KI)larr A_(1) overset("Calcination")to "Black solid"+CO_(2)+H_(2)O A_(2) overset("Roasting")to "Metal"+gasoverset(K_(2)Cr_(2)O_(7))underset(H_(2)SO_(4))to "Green colour"

A_(1) and A_(2) are two vectors such that |A_(1)| = 3 , |A_(2)| = 5 and |A_(1)+A_(2)| = 5 the value of (2A_(1)+3A_(2)).(2A_(1)-2A_(2)) is

If a_(0), a_(1), a(2),… are the coefficients in the expansion of (1 + x + x^(2))^(n) in ascending powers of x, prove that a_(0) a_(2) - a_(1) a_(3) + a_(2) a_(4) - …+ a_(2n-2) a_(2n)= a_(n+1) .

If a_(1) and a_(2) aare two non- collineaar unit vectors and if |a_(1)+a_(2)|=sqrt(3), ,then value of (a_(1)-a_(2)).(2a_(1)-a_(2)) is