Complex roots of quadratic equations

Complex roots of quadratic equations Quiz

Spec 1.4 · Edexcel International A Level Further Maths: Quiz

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  1. 1. Find the roots of z2+9=0z^2+9=0.

    • A. ±3\pm3
    • B. ±3i\pm3\mathrm{i}
    • C. ±9i\pm9\mathrm{i}
    • D. 3±3i3\pm3\mathrm{i}

  2. 2. Find the roots of z2−2z+5=0z^2-2z+5=0.

    • A. 1±2i1\pm2\mathrm{i}
    • B. −1±2i-1\pm2\mathrm{i}
    • C. 2±i2\pm\mathrm{i}
    • D. 1±4i1\pm4\mathrm{i}

  3. 3. For which value of kk does z2+4z+k=0z^2+4z+k=0 have non-real roots?

    • A. k=1k=1
    • B. k=4k=4
    • C. k=0k=0
    • D. k=7k=7

  4. 4. One root of a quadratic with real coefficients is 3−i3-\mathrm{i}. The other is:

    • A. −3+i-3+\mathrm{i}
    • B. 3+i3+\mathrm{i}
    • C. −3−i-3-\mathrm{i}
    • D. i−3\mathrm{i}-3

  5. 5. Find the modulus of each root of z2−2z+10=0z^2-2z+10=0.

    • A. 10\sqrt{10}
    • B. 1010
    • C. 44
    • D. 8\sqrt{8}

Quiz