MHB Prove/Disprove: Uniform Continuity of sin(sin(x))

AI Thread Summary
The discussion centers on proving or disproving the uniform continuity of the function sin(sin(x)) using the ε, δ definition. Participants clarify the ε, δ definition, which states that for every ε > 0, there exists a δ > 0 such that if |x - y| < δ, then |f(x) - f(y)| < ε for all x, y in the domain. A hint is provided using the formula sin(x) - sin(y) = 2cos((x+y)/2)sin((x-y)/2) to assist in the proof. The challenge invites participants to explore the uniform continuity of the nested sine function. The conversation emphasizes understanding the ε, δ definition as a foundational concept in real analysis.
solakis1
Messages
407
Reaction score
0
prove or disprove if the following function is uniformly continuous:

$$sin(sin(x)) $$ using the ε,δ definition
 
Mathematics news on Phys.org
Do you know what that means? What IS the "$\epsilon, \delta$ definition"?
 
Country Boy said:
Do you know what that means? What IS the "$\epsilon, \delta$ definition"?
This is a challenge problem. solaklis wants you to find the answer...

-Dan
 
hint
[sp]Use the formula :
sinx-siny =$2cos\frac{x+y}{2}sin\frac{x-y}{2}$[/sp]
 
Country Boy said:
Do you know what that means? What IS the "$\epsilon, \delta$ definition"?
The $\epsilon$ $\delta$ definition for real function f(x) is :

Given $\epsilon>0$ there exists a $\delta>0$ such that :
For all x,y belonging the to domain of f(x) and $|x-y|<\delta$ then $|f(x)-f(y)|<\epsilon$
 
Seemingly by some mathematical coincidence, a hexagon of sides 2,2,7,7, 11, and 11 can be inscribed in a circle of radius 7. The other day I saw a math problem on line, which they said came from a Polish Olympiad, where you compute the length x of the 3rd side which is the same as the radius, so that the sides of length 2,x, and 11 are inscribed on the arc of a semi-circle. The law of cosines applied twice gives the answer for x of exactly 7, but the arithmetic is so complex that the...
Is it possible to arrange six pencils such that each one touches the other five? If so, how? This is an adaption of a Martin Gardner puzzle only I changed it from cigarettes to pencils and left out the clues because PF folks don’t need clues. From the book “My Best Mathematical and Logic Puzzles”. Dover, 1994.
Thread 'Imaginary Pythagoras'
I posted this in the Lame Math thread, but it's got me thinking. Is there any validity to this? Or is it really just a mathematical trick? Naively, I see that i2 + plus 12 does equal zero2. But does this have a meaning? I know one can treat the imaginary number line as just another axis like the reals, but does that mean this does represent a triangle in the complex plane with a hypotenuse of length zero? Ibix offered a rendering of the diagram using what I assume is matrix* notation...
Back
Top