Q1 In a triangle ABC the internal bisector of angle(A)meets BC at D. If AB=4, AC=3 and anlgle(A) = 60, then the length of AD is
Q2. If x, y and z are real numbers such that x + y + z =5 and xy + yz + zx = 3, what is the largest value that x can have ?
Q3. The number of real roots of the equation A2/x + B2/(x-1)=1 , where A and B are real numbers not equal to zero simultaneously is a. None b. 1 c. 2 d. b or c
Q4. In how many ways is it possible to choose a white and a black square on a chessboard so that the squares must not lie in the same row or column ? |
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Given
A2/x + B2/(x-1) = 1
=> ( x - 1)A2+ x B2/x(x-1) = 1
=>( x - 1)A2+ x B2 = x(x-1)
Above is a quadrtic equation where x is the variable
so can have either 1 or 2 roots
answer d
I think it is 32 x 24 = 768
Let x=13/3
y=1/3
z=1/3
x+y+z=5
xy+yz+xz=3
So ans c.
I am getting the answer as 12√3/7
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