Trigonometry and Complex Numbers Flashcards
6 cards from real AIME practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Trigonometry and Complex Numbers flashcards as text
What is sin^2(θ) + cos^2(θ) for any angle θ?
Answer: 1
This is the fundamental Pythagorean identity, which equals 1 for all θ.
Using the Law of Cosines, find side c when a=5, b=7, C=60°.
Answer: √39
c^2=25+49-2(5)(7)(1/2)=74-35=39, so c=√39.
Express sin(2θ) using a double-angle formula.
Answer: 2sin(θ)cos(θ)
The double-angle identity is sin(2θ)=2sin(θ)cos(θ).
What is the argument (angle) of the complex number z = -1 + i?
Answer: 135°
-1+i lies in the second quadrant; reference angle=arctan(1/1)=45°, so argument=180°-45°=135°.
Compute |3 - 4i|^2.
Answer: 25
|3-4i|=√(9+16)=5; |3-4i|^2=25.
How many solutions does 2cos(x) = 1 have in the interval [0, 2π)?
Answer: 2
cos(x)=1/2 gives x=π/3 and x=5π/3 in [0,2π), so there are 2 solutions.