Loci in the Argand diagram Quiz

1. State the centre and radius of $|z+2-i|=3$.

• A. centre $-2+i$, radius $3$
• B. centre $2-i$, radius $3$
• C. centre $-2-i$, radius $9$
• D. centre $2+i$, radius $3$

2. Which line is the locus $|z-2|=|z-6|$?

• A. $x=2$
• B. $x=6$
• C. $x=4$
• D. $y=4$

3. Describe the locus $\arg(z-1)=\frac{\pi}{2}$.

• A. The full vertical line through $1$
• B. The positive imaginary axis
• C. The circle with centre $1$
• D. The vertical half-line above the point $1$, not including $1$

4. What does $|z-i|<2$ represent?

• A. The circle with centre $i$ and radius $2$
• B. The inside of the circle with centre $i$ and radius $2$, boundary excluded
• C. The outside of that circle
• D. The inside of the circle, boundary included

5. What does $|z|\le|z-4|$ represent?

• A. The points with $x\le2$
• B. The points with $x\ge2$
• C. The points with $x\le4$
• D. The circle $x^2+y^2=4$