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Complex numbers 2 — Question 10

QCAA 2025, Paper 1 · 1 mark

Q10 · 2025 · Technology-freeSimple familiar1 mark

QUESTION 10

Given z1z_1 and z2z_2 are complex numbers, which statement is always true?
(A)
∣z1+z2∣=∣z1∣+∣z2∣|z_1+z_2|=|z_1|+|z_2|
(B)
∣z1+z2∣≠∣z1∣+∣z2∣|z_1+z_2|\ne|z_1|+|z_2|
(C)
∣z1+z2∣≤∣z1∣+∣z2∣|z_1+z_2|\le|z_1|+|z_2|
(D)
∣z1+z2∣≥∣z1∣+∣z2∣|z_1+z_2|\ge|z_1|+|z_2|
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