MathematicsChapter 2: Quadratic Equations
Link To Complex
If D=-16, sqrt(D)=4i in C.
Learning objectives
- Define and explain link to complex.
- Apply link to complex to a focused FBISE question.
- Check the answer for correct terms, evidence, working, and units.
Definition
If D=-16, sqrt(D)=4i in C. Roots are still a conjugate pair. On a real-only paper, write 'no real roots'. On a complex paper, simplify with i.
Formula
D=-16
Where / symbols
- Link To Complex
- If D=-16, sqrt(D)=4i in C. Roots are still a conjugate pair. On a real-only paper, write 'no real roots'. On a complex paper, simplify with i.
Relationship
- D=0 repeated
Overview
Learn the idea, then use it:
Core Understanding
If D=-16, sqrt(D)=4i in C. Roots are still a conjugate pair. On a real-only paper, write 'no real roots'. On a complex paper, simplify with i.
Examples conjugates if D<0 · D>0 two reals · D=0 repeated · LINK TO COMPLEX: If D=-16, sqrt(D)=4i in C. Roots are still a conjugate pair. On a real-only paper, write 'no real roots'. On a complex p
Exam Application
State the correct term, connect it to the chapter rule or evidence, and use a clear example or calculation.
Examples Define first · Show the rule or evidence · Check units, labels, and conclusion
WHAT — LINK TO COMPLEX
If D=-16, sqrt(D)=4i in C. Roots are still a conjugate pair. On a real-only paper, write 'no real roots'. On a complex paper, simplify with i.
HOW — Use the idea
Identify what is given, select this topic's rule or evidence, apply it one step at a time, and check the result.
In simple words
Do not merge link to complex with a neighbouring idea that uses a different definition, rule, or method.
Key points
- conjugates if D<0
- D>0 two reals
- D=0 repeated
Exam preparation
Exam Focus
Quick revision
Revision Zone
Review the key facts, formulas and checks before you move on.Link To Complex
Sticky Notes · Quick Revision
Core Idea
- If D=-16, sqrt(D)=4i in C.
Key Points
- conjugates if D<0
- D>0 two reals
- D=0 repeated
Simple Check
- Explain link to complex in your own words and connect it to one chapter example.
How to Answer
- Define the idea, show the main rule or evidence, apply it, and check the final statement.
Common Mistake
- Do not merge link to complex with a neighbouring idea that uses a different definition, rule, or method.
FBISE Exam Tip
- Use the exact term, show working where needed, and include units or labelled evidence.
60-second revision
- If D=-16, sqrt(D)=4i in C.
- conjugates if D<0
- D>0 two reals
- D=0 repeated
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