TI-84 Plus CE field manual for IB Math
Modulus and argument ∣z∣, argz
Read the modulus ∣z∣ and principal argument argz of a complex number straight off the calculator (radian mode), then assemble the polar form reiθ.
Find the modulus ∣z∣ and argument argz of z=5+3i, and hence write z in the form reiθ.
Confirm the calculator is in radian mode and complex outputs are enabled: press , make sure RADIAN is highlighted on the angle row and a+bi on the complex row, then back to the home screen.
Compute the modulus. Open the complex menu: press , then to land on the CMPLX tab, then for abs(, which inserts the absolute-value bars |▯|. Type and press .
Compute the argument the same way: pastes angle(. Type and press .
∣z∣≈5.83 and argz≈0.540 rad (both positive, as expected for a first-quadrant number), so z≈5.83e0.540i.
Your turn
Work each one on your calculator, then check the answer.
- 1
Find the modulus and argument of z=2+5i, and write z in the form reiθ.
- 2
Find the modulus and argument of z=−3+2i, and write z in the form reiθ.
- 3
Find the modulus and argument of z=−1−4i, and write z in the form reiθ.