Class 11 Complex Numbers Lecture 5

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Lecture - 5 Chapter 5 Complex Numbers

MISCELLANEOUS EXERCISE

Question 1. Evaluate: \(\left [ i^{18}+ \left ( \frac{1}{i} \right )^{25} \right ]^3\).

Question 2. For any two complex numbers \(z_1 \text{ and } z_2\), prove that \( Re(z_1 z_2) = Re z_1 Re z_2 – Im z_1 Im z_2\).

Question 3. Reduce \(\left ( \frac{1}{1-4i} – \frac{2}{1+i} \right ) \left ( \frac{3-4i}{5+i} \right )\) to the standard form.

Question 4. If \(x-iy = \sqrt{\frac{a-ib}{c-id}}\) prove that \( (x^2+y^2)^2=\frac{a^2+b^2}{c^2+d^2}\).

Question 5. Convert the following in the polar form:
(i). \(\frac{1+7i}{(2-i)^2}\)
(ii). \( \frac{1+3i}{1-2i}\)

Solve each of the equation in Exercises 6 to 9:

Question 6. \(3x^2-4x+\frac{20}{3}=0\)

Question 7. \(x^2-2x+\frac{3}{2}=0\)

Question 8. \(27x^2-10x+1=0\)

Question 9. \(21x^2-28x+10=0\)

Question 10. If \(z_1=2-i, z_2=1+i\), find \( \left | \frac{z_1+z_2+1}{z_1-z_2+1} \right |\).

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