Express (a+ib/ a-ib)+(a-ib/ a+ib) in the form of a+ib
A. (a2+b2)/( a2 -b2)
B. (a2-b2)/( a2 +b2)
C. 2 (a2+b2)/( a2 -b2)
D. 2(a2-b2)/( a2 +b2)
For all values of a and b(a + 2b)x + (a- b)y + (a + 5b) = 0 passes through the point:
A. (-1, 2)
B. (2, -1)
C. (-2, 1)
D. (1, -2)
If the direction ratio of two lines are given by 3lm-4ln+mn =0 and l+2m+3n=0,then the angle between the lines, is
A. π/6
B. π/4
C. π/3
D. π/2
The ascending order of the moduli of the complex numbers z1=1+i,z2=1+2i,z3=1-i/√2,z4=3+4i is
A. z1,z2,z3,z4
B. z4,z2,z1,z3
C. z3,z1,z2,z4
D. z4,z3,z2,z1
I: The modulus of √3+i/(1+i)(1+√3i) is 1/√2 II: The least positive value of n for which (1-i/1+i)n=1 is 2
A. only I is true
B. only II is true
C. both I and II are true
D. neither I nor II are true
If 1,ω,ω2 are the cube roots of unity, then (a+bω+cω2)/ (c+aω+bω2) is equal to:
A. 1
B. ω
C. ω2
D. ω3
If (cos 3α+i sin 3α)(cos 5β+i sin 5β)= cos θ+i sin θ then θ is
A. 2α+3β
B. 3α+6β
C. 3α+5β
D. 2α+4β
If |z-1/z+a|=1 where Re(a)≠0 then the locus of z=x+iy is
A. y=0
B. x=0
C. x2+y2+2x-4y=0 such that y1
D. x2+y2+2x-4y=0 such that 2x-y+4>0
If a=2i+2j+k, a.b=14, axb=3i-j-8k then b=
A. 5i+j+2k
B. 5i-5j+2k
C. 5i+5j-2k
D. 5i-5j-2k
If ω is a complex cube root of unity then ( 1 - ω + ω2)6 + ( 1- ω2 + ω)6 =
A. 0
B. 6
C. 64
D. 128
If (1 + cos θ + i sin θ)(1 + cos 2θ + i sin 2θ)=x+iy then y=
A. 16 cos2θ sin2(θ/2)
B. 16 sin2θ cos2(θ/2)
C. 16 sin2θ sin2(θ/2)
D. 16 cos2θ cos2(θ/2)
If sinA + sinB = l, cosA - cosB = m, then the value of cos(A - B) =
A. (l2-m2)/(l2+m2)
B. (l2+m2)/(l2-m2)
C. 2lm/(l2+m2)
D. 2lm/(l2-m2)
If x2+x+1=0, then the value of (x+1/x)2+(x2+1/x2)2+...+(x27+1/x27)2 is
A. 27
B. 72
C. 45
D. 54
If (1+ cos θ+ i sin θ)(1+ cos 2θ+i sin2θ)= x+iy, then y=
A. x tan(3θ/2)
B. x tan(5θ/2)
C. x tan(7θ/2)
D. x tan(9θ/2)
If u+iv= 2+i/z+3, where z=x+iy, then the values of u, v are
A. 2(x+3)+y/(x+3)2+ y2, x-2y+3/ (x+3)2+y2
B. 2(x+2)+y/(x+2)2+ y2, x-2y+3/ (x+2)2+y2
C. 2(x+4)+y/(x+4)2+ y2, x-2y+3/ (x+4)2+y2
D. none
In the Argand plane, the points represented by the complex number s 2-6i, 4-7i, 3-5i and 1-4i form
A. parallelogram
B. rectangle
C. rhombus
D. square
If ((1+i)x-2i)/(3+i)+((2-3i)y+i/3-i)=I, then (x,y)=
A. (0,0)
B. (3,1)
C. (3,-1)
D. (-3,1)
If (a1+ib1)( (a2+ib2)…. (an+ibn)= A+iB, then (a12 +b12)( a22 +b22 )….(an2 +bn2)=
A. A2+B2
B. A2-B2
C. A3+B3
D. A3-B3
If z1=1+2i,z2=2+3i,z3=3+4i,then z1,z2 and z3 represents the vertices of
A. Equilateral triangle
B. Right angled triangle
C. Equilateral triangle
D. None
Express (2+3i/ 2-3i)-(2-3i/ 2+3i) in the form of a+ib
A. 24i/13
B. 27i/13
C. 28i/13
D. 30i/13