Q63.The value of cos( 2π7 ) + cos( 4π7 ) + cos( 6π7 ) is equal to (1) −1 (2) −12 (3) −13 (4) −14
What This Question Tests
This question involves solving a complex equation to find its roots, identifying the non-real roots, and then calculating the area of the polygon formed by these roots in the complex plane, which requires geometric interpretation.
Concepts Tested
Formulas Used
z = re^(iθ)
Area of equilateral triangle = (√3/4)a²
📚 NCERT Sections This Tests
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1.27 If the solubility product of CuS is 6 × 10–16, calculate the maximum molarity of CuS in aqueous solution.
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📋 Question Details
- Chapter
- Complex Numbers
- Topic
- Roots of complex equations
- Year
- 2022
- Shift
- 27 Jun Shift 1
- Q Number
- Q63
- Type
- MCQ
- NCERT Ref
- Class 11 Mathematics Ch 5: Complex Numbers and Quadratic Equations
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