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  • Perplex
    IB Math AIHL
    /
    Complex Numbers
    /

    Video

    Video Reviews

    Watch comprehensive video reviews for most units, designed for final exam preparation. Each video includes integrated problems you can solve alongside detailed solutions.

    Not your average video:

    Interactive Problems: Solve problems alongside the video with step-by-step guidance and detailed solutions.

    Exam Preparation: Complete unit reviews designed for final exam preparation with all key concepts covered systematically.

    Expert Teaching: High-quality instruction from Perplex co-founder James Mullen with clear explanations, worked examples, and exam tips.

    Not your average video:

    Interactive Problems: Solve problems alongside the video with step-by-step guidance and detailed solutions.

    Exam Preparation: Complete unit reviews designed for final exam preparation with all key concepts covered systematically.

    Expert Teaching: High-quality instruction from Perplex co-founder James Mullen with clear explanations, worked examples, and exam tips.

    Complex Numbers

    Video Reviews

    Watch comprehensive video reviews for Complex Numbers, designed for final exam preparation. Each video includes integrated problems you can solve alongside detailed solutions.

    Not your average video:

    Interactive Problems: Solve problems alongside the video with step-by-step guidance and detailed solutions.

    Exam Preparation: Complete unit reviews designed for final exam preparation with all key concepts covered systematically.

    Expert Teaching: High-quality instruction from Perplex co-founder James Mullen with clear explanations, worked examples, and exam tips.

    Not your average video:

    Interactive Problems: Solve problems alongside the video with step-by-step guidance and detailed solutions.

    Exam Preparation: Complete unit reviews designed for final exam preparation with all key concepts covered systematically.

    Expert Teaching: High-quality instruction from Perplex co-founder James Mullen with clear explanations, worked examples, and exam tips.

    Cartesian formPolar formDe Moivre

    The video will automatically pause when it reaches a problem.

    Multiplying in mod-arg form

    AHL AA 1.13

    The main advantage of Euler's form - other than its beauty - is that it makes multiplying complex numbers much easier:

    r1​eiα⋅r2​eiβ=r1​r2​ei(α+β)🚫


    In words, when we multiply two complex numbers the arguments add and the moduli multiply.


    Similarly for division:

    r2​eiβr1​eiα​=r2​r1​​ei(α−β)🚫


    In words, when we divide one complex number from another, we subtract the arguments and divide the moduli.


    Example

    Given that z⋅(1+i)=(2−2i), find z.


    First convert everything to Euler's form:

    reiθ⋅(√2eiπ/4)⇒reiθ  ​=2√2e−iπ/4=√2eiπ/42√2e−iπ/4​=2ei(−π/4−π/4)=2e−iπ/2=−2i​

    Multiplying in mod-arg form

    AHL AA 1.13

    The main advantage of Euler's form - other than its beauty - is that it makes multiplying complex numbers much easier:

    r1​eiα⋅r2​eiβ=r1​r2​ei(α+β)🚫


    In words, when we multiply two complex numbers the arguments add and the moduli multiply.


    Similarly for division:

    r2​eiβr1​eiα​=r2​r1​​ei(α−β)🚫


    In words, when we divide one complex number from another, we subtract the arguments and divide the moduli.


    Example

    Given that z⋅(1+i)=(2−2i), find z.


    First convert everything to Euler's form:

    reiθ⋅(√2eiπ/4)⇒reiθ  ​=2√2e−iπ/4=√2eiπ/42√2e−iπ/4​=2ei(−π/4−π/4)=2e−iπ/2=−2i​
    Cartesian formPolar formDe Moivre