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1 month ago
WildTrig3: Spread, angles and astronomy
Angles have their origin in astronomy and spherical trigonometry. Here we introduce the rational alternative, called spread, and give examples fro...
njwildberger • 11,576 views
footstep002
commented:
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1 month ago
WildTrig5: Applications of rational trigonometry
Rational trigonometry is applied to solve four examples of practical problems, concerning a flagpole, a ladder, a kite and the distance from a poin...
njwildberger • 9,771 views
footstep002
commented:
I was confused about the cross law a little bit. So After reviewing this and previous videos several times, and I realized that due to the cyclic property of the cross law and the cross law being quadratic equation gives the formula able to manipulate its internal signs, practically there exists ...
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1 month ago
WildTrig4: Five main laws of rational trigonometry
We derive from first principles the main laws of rational trigonometry, using the concepts of quadrance and spread to replace the usual distance an...
njwildberger • 10,579 views
footstep002
commented:
This may be a silly question, but as I heard from the previous video triple quad formula is (internal large interval + internal small interval - whole interval) squared equal 4 times (internal large interval times internal small interval), and the triple quad formula from this video seems differe...
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1 month ago
UnivHypGeom3: Pappus' theorem and the cross ratio
Pappus' theorem is the first and foremost result in projective geometry. Another of his significant contributions was the notion of cross ratio of ...
njwildberger • 2,068 views
footstep002
commented:
Another question.
In previous examples of cross ratios, It seems that it's all about straight lines. But suddenly in Chasles theorem the cross ratio is applied in conic including a circle.
I'm curious. Is cross ratio work on curved interval, like the arc interval between alpha and beta. Or Is it ...
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2 months ago
UnivHypGeom2: Apollonius and harmonic conjugates
Apollonius introduced the important idea of harmonic conjugates, concerning four points on a line. He showed that the pole polar duality associated...
njwildberger • 2,019 views
footstep002
commented:
I've tried several times to solve exercise2.1 using CaR program. But I can't plot the tangent line for gamma. As you know it is easy to find a null point starting 'from a pole outside circle'. It's just a result of first definition of pole, that includes a tangent line.
But in exercise2.1 null po...
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3 months ago
Finite Simple Group (of Order Two)
Finite Simple Group (of Order Two)
The Klein Four Group
The path of love is never smooth
But mine's continuous for you
You're the upper bound in ...
oneofvipper • 685,575 views
footstep002
liked
In the video at 4:30 there's a illustration about spreads in four sides, that are equal. I get that oppsite side spread is same. What I don't get is that spread between quadrance R and P is equal to the spreads that are adjacent(the wider one).
Please explain why they are same.