The radical center of the circles `x^2+y^2=a^2`, `(x-c)^2+y^2=a^2` and `x^2+(y-b)^2=a^2` is
(A)  `(a/2,b/2)`  (B)  `(b/2,c/2)`  (C)  `(c/2,b/2)`  (D)   None of these

The distance of the point (2,3) from the line x-2y+5=0 measured in a direction parallel to the line x -3y=0 is: (A)   2sqrt(10)     (B)   sqrt(10)     (C)   2sqrt(5)     (D)   None of these

If P , Q be the A.M., G.M. respectively between any two rational numbers a and b , then P-Q is equal to (A)   (a-b)/a   (B)   (a+b)/2   (C)   (2ab)/(a+b)   (D)   ((sqrt(a)-sqrt(b))/sqrt(2))^2

If a^(1/2)+b^(1/2)-c^(1/2)=0 , then the value of (a+b-c)^2 is: (A)    2ab    (B)    2bc    (C)    4ab    (D)    4ac

The domain of the function f(x)=sqrt({(-log_0.3(x-1))/(-x^2+3x+18)}) is (a)   [2,6]   (b)   ]2,6[ (b)   [2,6[   (d)  None of these

The number of integer values of m , for which the x-coordiante of the point of intersection of the lines 3x+4y=9 and y=mx+1 is also an integer, is (a)    2     (b)   0 (c)    4     (d)   1

If the lines ax+y+1=0 , x+by+1=0 and x+y+c=0 , ( a , b , c being distinct and different from 1 ) are concurrent, then 1/(1-a)+1/(1-b)+1/(1-c)= (A)    0    (B)    1    (C)    1/(a+b+c)    (D)   None of these

If the lines ax+y+1=0 , x+by+1=0 and x+y+c=0 , ( a , b , c being distinct and different from 1 ) are concurrent, then 1/(1-a)+1/(1-b)+1/(1-c)= (A)    0    (B)    1    (C)    1/(a+b+c)    (D)   None of these

The co-ordinates of two fixed points A and B of a triangle ABC are (a,0) and (-a,0) respectively. If variable point C moves such that cot A+ cot B=lamda , (where lamda is a constant) then the locus of point C is:- (1)    y lamda =2a     (2)    y =lamda a     (3)    y a=2lamda     (4)     None of these.

The acute angle between the lines y=3 and y=sqrt(3)x+k is (A)   30 °   (B)   60 °    (C)   45 °   (D)   90 °   

Sum of the series 1+2^2x+3^2x^2+4^2x^3+.....to oo , |x| (A)    (1+x)/(1-x)^3    (B)    (1-x)/(1+x)^3     (C)    (2+x)/(1-x)^3    (D)    (1-x)/(1+x)^2