Establish associative law of multiplication

Click For Summary
The discussion focuses on establishing the associative law of multiplication for complex numbers, specifically through the lens of absolute values and arguments. The equation z1(z2z3)=(z1z2)z3 is examined, emphasizing the need to demonstrate that both magnitudes and arguments behave associatively. Participants agree that the solution involves multiplying out the expressions and confirming their equivalence. It is clarified that the magnitudes multiply while the arguments add, reinforcing the associative property. Overall, the conversation highlights the mathematical principles underpinning the associative law in complex multiplication.
kathrynag
Messages
595
Reaction score
0

Homework Statement


Establish associative law of multiplication by considering absolute values and arguements.
z1(z2z3)=(z1z2)z3


Homework Equations





The Attempt at a Solution


I think I need to use r(costheta +isintheta)
r1(costheta1+isintheta1)[r2r3(costheta2+isintheta2)(costheta3+isintheta3)]=
Is this just a bunch of multiplying out and showing it's the same?
 
Physics news on Phys.org
Yes. The magnitudes multiply and the arguments add. Both operations are associative.
 
Ok, I think I see.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

Similar threads

Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 4 ·
Replies
4
Views
3K
Replies
4
Views
4K
Replies
4
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
Replies
3
Views
10K
  • · Replies 6 ·
Replies
6
Views
3K