If `|z|=2` and locus of `5z-1` is the circle having radius a and `z_1^2+z_2^2-2z_1z_2 cos theta=0, then |z_1|:|z_2|=` (A) a (B) 2a (C) `a/10` (D) none of these

If |z| = 2 and the locus of 5z-1 is the circle having radius 'a' and z_1^2 + z_2^2 - 2 z_1 z_2 cos theta = 0 then |z_1| : |z_2| =

If |z|=2 and the locus of 5z-1 is the circle having radius 'a' and z_(1)^(2)+z_(2)^(2)-2z_(1)z_(2)cos theta=0 then |z_(1)|:|z_(2)|=

The complex numbers z_1, z_2 and the origin form an equilateral triangle only if (A) z_1^2+z_2^2-z_1z_2=0 (B) z_1+z_2=z_1z_2 (C) z_1^2-z_2^2=z_1z_2 (D) none of these

The complex numbers z_1, z_2 and the origin form an equilateral triangle only if (A) z_1^2+z_2^2-z_1z_2=0 (B) z_1+z_2=z_1z_2 (C) z_1^2-z_2^2=z_1z_2 (D) none of these

If f(z)=(7-z)/(1-z^2) , where z=1+2i , then |f(z)| is (a)(|z|)/2 (b) |z| (c) 2|z| (d) none of these

If a m p(z_1z_2)=0a n d|z_1|=|z_2|=1,t h e n z_1+z_2=0 b. z_1z_2=1 c. z_1=z _2 d. none of these

If a m p(z_1z_2)=0a n d|z_1|=|z_2|=1,t h e n z_1+z_2=0 b. z_1z_2=1 c. z_1=z _2 d. none of these

If |z_1|=|z_2| then z_1/z_2+z_2/z_1= (A) 2costheta (B) -2costheta (C) 2sintheta (D) -2sintheta

If |z_1/z_2|=1 and arg (z_1z_2)=0 , then a. z_1 = z_2 b. |z_2|^2 = z_1*z_2 c. z_1*z_2 = 1 d. none of these

If |z_1/z_2|=1 and arg (z_1z_2)=0 , then a. z_1 = z_2 b. |z_2|^2 = z_1*z_2 c. z_1*z_2 = 1 d. none of these