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Further Maths: Core Pure -Edexcel-A Level

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  1. complex-numbers-and-argand-diagrams
    6 主题
  2. exponential-form-and-de-moivres-theorem
    4 主题
  3. properties-of-matrices
    3 主题
  4. transformations-using-matrices
    3 主题
  5. roots-of-polynomials
    2 主题
  6. series
    2 主题
  7. maclaurin-series
    1 主题
  8. hyperbolic-functions
    4 主题
  9. volumes-of-revolution
    2 主题
  10. methods-in-calculus
    5 主题
  11. vector-lines
    4 主题
  12. vector-planes
    4 主题
  13. polar-coordinates
    2 主题
  14. first-order-differential-equations
    3 主题
  15. second-order-differential-equations
    2 主题
  16. simple-harmonic-motion
    2 主题
  17. proof-by-induction
    2 主题
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Solving quadratic equations with complex roots

What are complex roots? 

  • Complex numbers provide solutions for quadratic equations which have no real roots

8-1-4-complex-roots-of-polynomials-diagram-1
  • Complex roots occur when solving a quadratic with a negative discriminant

    • This leads to square rooting a negative number

How do we solve a quadratic equation with complex roots?

  • We solve an equation with complex roots in the same way we solve any other quadratic equations

    • If in the form a z squared plus b equals 0 blank open parentheses a not equal to 0 close parentheses we can rearrange to solve

    • If in the form a z squared plus b z plus c equals 0 blank left parenthesis a not equal to 0 right parenthesis we can complete the square or use the quadratic formula

  • We use the property straight i equals square root of negative 1 end root along with a manipulation of surds

    • <img alt=”square root of negative a end root equals square root of a cross times negative 1 end root equals square root of a cross times square root of negative 1 end root” data-mathml='<math ><semantics><mrow><msqrt><mo>-</mo><mi>a</mi></msqrt><mo>=</mo><msqrt><mi>a</mi><mo>×</mo><mo>-</mo><mn>1</mn></msqrt><mo>=</mo><msqrt><mi>a</mi></msqrt>&lt

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