Date | May 2019 | Marks available | 3 | Reference code | 19M.2.AHL.TZ1.H_2 |
Level | Additional Higher Level | Paper | Paper 2 | Time zone | Time zone 1 |
Command term | Solve | Question number | H_2 | Adapted from | N/A |
Question
Solve z2=4eπ2i, giving your answers in the form
reiθ where r, θ∈R, r>0.
[3]
a.
a+ib where a, b∈R.
[2]
b.
Markscheme
* This question is from an exam for a previous syllabus, and may contain minor differences in marking or structure.
z=2eπ4i(=2e0.785i) A1
Note: Accept all answers in the form 2e(π4+2πn)i.
z=2e5π4i(=2e3.93i) OR z=2e−3π4i(=2e−2.36i) (M1)A1
Note: Accept all answers in the form 2e(−3π4+2πn)i.
Note: Award M1A0 for correct answers in the incorrect form, eg −2eπ4i.
[3 marks]
a.
z=1.41+1.41i, z=−1.41−1.41i A1A1
(z=√2+√2i,z=−√2−√2i)
[2 marks]
b.
Examiners report
[N/A]
a.
[N/A]
b.
Syllabus sections
Topic 1—Number and algebra » AHL 1.14—Complex roots of polynomials, conjugate roots, De Moivre’s, powers & roots of complex numbers
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