For any two real numbers `C` and `D` , `cosC+cos D=`

Arithmetic Mean between two positive real numbers a and b is ..........., (A) (a+b)/2 , (B) (a-b)/2 (C) (ab)/2 (D) none of these.

Sin C± Sin D || Cos C ± Cos D

CLoSURE PROPERTY If (a)/(b) and (c)/(d) are any two rational numbers then (a)/(b)-(c)/(d) is a rational number.

If a, b, c and are real numbers and A =[{:( a,b),(c,d) :}] prove that A^(2) -(a+d) A+(ad-bc) I=0

40.a,b,c are non-zero real numbers such that a+b+6c=0, roots of ax+bx+cO are (A) Reai and distinct(B) Reai & equal (C) Real and negative (D) none of the

Let a, b, c, d be distinct real numbers such that a, b are roots of x^2-5cx-6d=0 and c, d are roots of x^2-5ax-6b=0 . Then b+d is

For any real numbers a ,d a*C_(0)+(a+d)C_(1)+(a+2d)C_(2)+ ____+(a+nd)*C_(n)=

If a, b, c and d are four positive real numbers such that sum of a, b and c is even the sum of b,c and d is odd, then a^2-d^2 is necessarily

If a,b,c and d are four positive real numbers such that abcd =1, what is the minimum value of (1+a)(1+b)(1+c)(1+d)