Mathematics Grade 12 15 min

Midpoints in the complex plane

Midpoints in the complex plane

Tutorial Preview

1

Introduction & Learning Objectives

Learning Objectives Represent complex numbers as position vectors in the Argand diagram. Derive and state the formula for the midpoint of a line segment connecting two complex numbers. Accurately calculate the midpoint of the line segment connecting two given complex numbers. Algebraically determine a missing endpoint when given one endpoint and the midpoint. Interpret the midpoint of two complex numbers as their arithmetic mean. Apply the midpoint formula to solve geometric problems in the complex plane, such as finding the center of a diagonal. If two ships are located at positions represented by complex numbers, where is the exact halfway point for a rescue helicopter to meet them? 🚁 This tutorial connects the familiar concept of a midpoint from coordinate geometry to t...
2

Key Concepts & Vocabulary

TermDefinitionExample Complex Plane (Argand Diagram)A two-dimensional plane used to represent complex numbers. The horizontal axis is the real axis (Re) and the vertical axis is the imaginary axis (Im).The complex number z = 3 + 4i is represented by the point (3, 4) on the complex plane. Position VectorIn the context of the complex plane, a vector originating from the origin (0 + 0i) and terminating at the point representing a complex number z = a + bi.The complex number z = -2 + i can be visualized as a position vector from the origin to the point (-2, 1). MidpointThe point on a line segment that is equidistant from both endpoints.The midpoint of the line segment between (0,0) and (10,0) is (5,0). Complex Number AdditionThe process of adding two complex numbers by summing their real and...
3

Core Formulas

The Midpoint Formula z_m = \frac{z_1 + z_2}{2} To find the midpoint (z_m) of the line segment connecting two complex numbers (z₁ and zā‚‚), add the complex numbers together and divide the result by 2. This is equivalent to averaging the two numbers. The Endpoint Formula z_2 = 2z_m - z_1 Use this formula to find a missing endpoint (zā‚‚) when you are given the other endpoint (z₁) and the midpoint (z_m). It is derived by rearranging the Midpoint Formula.

5 more steps in this tutorial

Sign up free to access the complete tutorial with worked examples and practice.

Sign Up Free to Continue

Sample Practice Questions

Challenging
In triangle ABC, the vertices are complex numbers z_A, z_B, and z_C. The midpoint of side AB is M = 1 + i, and the midpoint of side AC is N = 3 - 2i. What complex number represents the vector from B to C (i.e., z_C - z_B)?
A.2 - 3i
B.-2 + 3i
C.8 - 12i
D.4 - 6i
Challenging
The midpoint of z₁ and zā‚‚ is 2+i. The midpoint of z₁ and zā‚ƒ is 4+5i. The midpoint of zā‚‚ and zā‚ƒ is 6-2i. Find the complex number z₁.
A.12 + 4i
B.8i
C.0
D.-2i
Challenging
A fixed point is at z₁ = 4 + 6i. A second point zā‚‚ moves along the circle |z| = 2. What is the locus of the midpoint z_m of the segment connecting z₁ and zā‚‚?
A.line segment of length 2
B.circle centered at 4 + 6i with radius 1
C.circle centered at 2 + 3i with radius 1
D.circle centered at 2 + 3i with radius 2

Want to practice and check your answers?

Sign up to access all questions with instant feedback, explanations, and progress tracking.

Start Practicing Free

More from Complex plane

Ready to find your learning gaps?

Take a free diagnostic test and get a personalized learning plan in minutes.