St. Britto Hr. Sec. School - Madurai
12th Maths Weekly Test -1 (Complex Numbers)-Aug 2020
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If |z1|=1,|z2|=2|z3|=3 and |9z1z2+4z1z3+z2z3|=12, then the value of |z1+z2+z3| is
1
2
3
4
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If \(\cfrac { z-1 }{ z+1 } \) is purely imaginary, then |z| is
\(\cfrac { 1 }{ 2 } \)
1
2
3
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The principal argument of (sin 40°+i cos40°)5 is
−110°
−70°
70°
110°
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The principal argument of the complex number \(\cfrac { \left( 1+i\sqrt { 3 } \right) ^{ 2 } }{ 4i\left( 1-i\sqrt { 3 } \right) } \) is
\(\cfrac { 2\pi }{ 3 } \)
\(\cfrac { \pi }{ 6 } \)
\(\cfrac { 5\pi }{ 6 } \)
\(\cfrac { \pi }{ 2 } \)
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The product of all four values of \(\left( cos\cfrac { \pi }{ 3 } +isin\cfrac { \pi }{ 3 } \right) ^{ \frac { 1 }{ 4 } }\) is
-2
-1
1
2
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The value of \(\left( \cfrac { 1+3\sqrt { i } }{ 1-\sqrt { 3i } } \right) ^{ 10 }\)
\(cis\cfrac { 2\pi }{ 3 } \)
\(cis\cfrac { 4\pi }{ 3 } \)
\(-cis\cfrac { 2 }{ 3 } \)
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Simplify the following
i1947+i1950
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Given the complex number z=2+3i, represent the complex numbers in Argand diagram
z, iz , and z+iz -
If zi zi =1−3i, = −4 , and z3 = 5 , show that (z1+z2)+z3=z1+(z2+z3)
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If z=x+iy , find the following in rectangular form.
\(Re\left( \cfrac { 1 }{ z } \right) \)
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Prove the following properties z is real if and only if z \(\bar { z } \)
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Find the modulus of the following complex numbers
\(\cfrac { 2i }{ 3+4i } \)
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Explain the falacy:
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Find the locus of z if Re\(\\ \left( \frac { \bar { z } +1 }{ \bar { z } -i } \right) \) =0.
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Given the complex number z=2+3i, represent the complex numbers in Argand diagram
z, iz , and z+iz -
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If z1 =2+5i, z2 =-3-4i, and z3 =1+i, find the additive and multiplicate inverse of z1 ,z2 and z3
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Show that the complex numbers 3 + 2i, 5i, -3 + 2i and -i form a square.
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The complex numbers u,v, and w are related by \(\frac { 1 }{ u } =\frac { 1 }{ v } +\frac { 1 }{ w } \) If v=3−4i and w=4+3i, find u in rectangular form.
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If 1, ω, ω2 are the cube roots of unity then show that (1+5ω2+ω4) (1+5ω+ω2) (5+ω+ω5) =64
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Find all the roots \((2-2i)^{ \frac { 1 }{ 3 } }\) and also find the product of its roots.
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If 2cosa = x + \(\frac { 1 }{ x } \) and 2cosβ = y + \(\frac { 1 }{ y } \) show that
i) \(\frac { x }{ y } +\frac { y }{ x } \) = 2cos(α − β).
ii) \(xy-\frac { 1 }{ xy } \) = 2isin(α + β)
iii) \(\frac { { x }^{ m } }{ { y }^{ n } } -\frac { { y }^{ n } }{ { x }^{ m } } \) = 2isin(mα − nβ)
iv) \({ x }^{ m }{ y }^{ n }+\frac { 1 }{ { x }^{ m }{ y }^{ n } } \) = 2cos(mα + nβ)
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If z=x+iy is a complex number such that Im \(\left( \frac { 2z+1 }{ iz+1 } \right) \) = 0 show that the locus of z is 2x2 +2y2 +x-2y=0