If `a=-4 , b=-2, c=-1, d=6` then find the value of `(c^2-d^2)/(a+b+c)`

If a ,b ,c ,and d are in H.P., then find the value of (a^(-2)-d^-2)/(b^(-2)-c^-2) .

Given the for a,b,c,d in R, if a sec(200^@)- ctan(200^@)=d and b sec(200^@)+d tan(200^@)= c, then find the value of ((a^2+b^2+c^2+d^2)/(b d-a c))sin2 0^(@) .

If a-b=4, b-6=c, c-2=d, and a+d=4 ,what is the value of a?

If a,b,c and the d are in H.P then find the vlaue of (a^(-2)-d^(-2))/(b^(-2)-c^(-2))

If real numbers a, b, c, d, e satisfy a+1=b + 2 = c+ 3 = d + 4 = e + 5 = a + b + c + d + e + 3 then find the value of a^2 + b^2 + c^2 + d^2 + e^2

Let a , b , c , d be positive integers such that (log)_a b=3/2a n d(log)_c d=5/4dot If (a-c)=9, then find the value of (b-d)dot

If a ,b ,c ,d ,e are in A.P., the find the value of a-4b+6c-4d+edot

If a, b, c, d satisfy the equation a + 7b + 3c + 5d = 0 , 8a + 4b + 6c + 2d = - 16 , 2a + 6b + 4c + 8d =16 and 5a + 3b + 7c + d = -16 then the value of (a + d) (b + c) =______

If agt0, bgt0, cgt0 and the minimum value of a^2(b+c)+b^2(c+a)+c^2(a+b) is kabc, then k is (A) 1 (B) 3 (C) 6 (D) 4

If (c)/(d)-(a)/(b)=x, a=2c, and b=5d , what is the value of (c)/(d) in terms of x?