EduNinja

A-Level CAIE Mathematics A23.9 Complex numbersQuestion Bank

Question 2

[Maximum number: 3]

On a sketch of an Argand diagram, shade the region whose points represent complex numbers z satisfying the inequalities z+23i2|z+2-3 \mathrm{i}| \leqslant 2 and argz34π\arg z \leqslant \frac{3}{4} \pi.

Question 2

On a sketch of an Argand diagram, shade the region whose points represent complex numbers z satisfying the inequalities z+1i1|z+1-i| \leqslant 1 and arg(z1)34π\arg (z-1) \leqslant \frac{3}{4} \pi.

Question 2

Question 2(a)

(a)

On an Argand diagram, shade the region whose points represent complex numbers z satisfying the inequalities 13πarg(z12i)13π-\frac{1}{3} \pi \leqslant \arg (z-1-2 \mathrm{i}) \leqslant \frac{1}{3} \pi and Rez3\operatorname{Re} z \leqslant 3.

[ 3 ]

Question 2(b)

(b)

Calculate the least value of argz\arg z for points in the region from (a). Give your answer in radians correct to 3 decimal places.

[ 2 ]

Question 2

[Maximum number: 4]

On an Argand diagram, shade the region whose points represent complex numbers z satisfying the inequalities z2iz+2i|z-2 \mathrm{i}| \leqslant|z+2-\mathrm{i}| and 0arg(z+1)14π0 \leqslant \arg (z+1) \leqslant \frac{1}{4} \pi.

Question 2

[Maximum number: 5]

On an Argand diagram, shade the region whose points represent complex numbers z satisfying the inequalities z1+2iz|z-1+2 i| \leqslant|z| and z21|z-2| \leqslant 1.

Question 2

[Maximum number: 4]

On a sketch of an Argand diagram, shade the region whose points represent complex numbers z satisfying the inequalities z2|z| \geqslant 2 and z1+i1|z-1+\mathrm{i}| \leqslant 1.

Question 3

[Maximum number: 4]

On a sketch of an Argand diagram, shade the region whose points represent complex numbers z satisfying the inequalities z3i3|z-3-\mathrm{i}| \leqslant 3 and zz4i|z| \geqslant|z-4 \mathrm{i}|.

Question 3

Question 3(a)

(a)

Given the complex numbers u=a+i b and w=c+i d, where a, b, c and d are real, prove that (u+w)=u+w(u+w)^{*}=u^{*}+w^{*}.

[ 2 ]

Question 3(b)

(b)

Solve the equation (z+2+i)+(2+i)z=0(z+2+\mathrm{i})^{*}+(2+\mathrm{i}) z=0, giving your answer in the form x+i y where x and y are real.

[ 4 ]

Question 3

[Maximum number: 5]

The square roots of 24-7i can be expressed in the Cartesian form x+i y, where x and y are real and exact.

By first forming a quartic equation in x or y, find the square roots of 24-7 i in exact Cartesian form.

Question 3

The complex number w is defined by w=2+i.

Question 3(i)

(a)

Showing your working, express w2w^{2} in the form x+i y, where x and y are real. Find the modulus of w2w^{2}.

Question 3(ii)

(b)

Shade on an Argand diagram the region whose points represent the complex numbers z which satisfy

zw2w2\left|z-w^{2}\right| \leqslant\left|w^{2}\right|
0 selected