"Both Plane Sailing and Great Circle Sailing, the most popular navigation methods, use plane, not spherical trigonometry" - What does a text on maritime navigation have to say?
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π°︎ r/flatearth
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π€︎ u/reficius1
π︎ Apr 02 2021
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Quadratic, Complex numbers, Parabolas, Circles, Domain and Range, Functions, Trigonometry challenge problems?

Where can I find quadratic challenge problems, complex numbers challenge problems, parabolas challenge problems, domain and range challenge problems, function challenge problems, and trig challenge problems? The purpose is to practice my ability to solve challenge problems in these topics.

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π°︎ r/CasualMath
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π︎ Mar 20 2021
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Anyone have a PDF copy of Precalculus concepts through functions, a unit circle approach to trigonometry by Sullivan, 3rd edition.

Money is really tight right now, unfortunately. Much appreciated!

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π°︎ r/learnmath
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π€︎ u/JayCee842
π︎ Jan 17 2021
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[HS Trigonometry] In the drawing in front of you are three overlapping circles that are laid out so that each of them passes at least through the center of one more circle. It is known that the area of ββeach of the circles is Ο. What is the length of the line highlighted in the drawing (in cm)?
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π€︎ u/ItsMayaItsmaya
π︎ Oct 24 2020
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[College Trigonometry] Distance traveled around circles

I'm given a circle with a radius 1 unit and asked to give the answers in fraction of pi as well as decimal places. I think I'm on the right path but worded math questions throw my brain for a loop. Here are a few examples and my answers:

What is the distance traveled in one-fourth revolution around this circle?

My answer: I assume the circumference is 2pi and that is equal to 1 revolution so I multiplied 1/4 rev by 2pi and got pi/2 or 1.57.

What is the distance traveled in a 45 degree rotation around this circle?

My answer: Like the previous question, I multiplied 2pi by 45 degrees and then divided by 360 degrees to get pi/4 or 0.79.

Am I interpreting the question correctly and are my steps correct?

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π€︎ u/No-Doughnut-3143
π︎ Nov 22 2020
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Coordinates + trigonometry = circles v.redd.it/zurrsqbz58l51
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π€︎ u/Extraltodeus
π︎ Sep 05 2020
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Which math book would you recommend to someone like me who only knows the basics of trigonometry (cos, sin tan, unit circle, radians, etc) and who found it quite intuitive but wants to move on to a little more advanced trigonometry?
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π︎ Oct 28 2020
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[Precalculus] Trigonometry - trigonometric functions and inverses by unit circle and special triangles (20 min video)

Hi, I made quick review video for my students if they need a review of sine, cosine, tangent, their reciprocals, and all their inverses. My goal was to make a comprehensive and connected summary of the 12 functions without depending on very much previous knowledge. https://www.youtube.com/watch?v=UdopiUpZwP4

It's written in LaTex so that it's easy to read and anyone could print them out and make notes of their own. Slides are available here: Wordpress (download button): https://robbiepmath.wordpress.com/2020/10/13/precalculus-trigonometry-slides-notes/

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π€︎ u/RPMath
π︎ Oct 17 2020
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now with punctuation and vocal grouping. maybe one day i get a grasp on trigonometry again to make it decent circles
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π€︎ u/erroronline1
π︎ Aug 01 2020
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Need help with some trigonometry and unit circles and stuff
1. Allow f(x) = x^(3), and g(x) = 2x. Determine f(g(1)).

2. Enter the formula for a sine function with an amplitude of 5, a period of 90 degrees, a shift of 45 degrees to the right and 3 units upwards.

Determine the exact value of the expression sin (v) + cos (v) given that tan (v) = 7/3.

1. Solve the equations in the range 180β€xβ€360 degrees. Answer with one decimal.

a) tan (x) = 3.2 (I would like a full solution for this, please)

b) sin (x) = 1.6

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π€︎ u/mogsuru
π︎ Jul 31 2020
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[Spherical Trigonometry] Do two fixed great circles in a sphere intersect always at two unique opposite points?

TL; DR: Just read the below first paragraph in bold and tell me if my assumption is correct or not (and why not, if that's the case, please)

.

My assumption is that any two great circles in a sphere intersect one to the other always at two unique points . Those two points are antipodal and divide each great circle in two equal halves.

Visual example:

https://imgur.com/1mNvgQ5

Starting from that assumption, If I can trace the perpendicular distance from the "Midpoint" between the antipodals of one great circle (one of the two arcpoints at 90Β° of the antipodals) to the plane of the other great circle, and I also know the radius of the sphere, using arcsin [perpendicular distance from midpoint great circle one to plane of great circle two/ radius sphere] I can obtain the angle of relative inclination (obliquity) of the two great circles about the pivotal line that connect the two antipodals.

Knowing the obliquity then It's quite straight-forward to express points of one great circle in terms of coordinates of the other great circle.

All of that I wrote just above are assumptions that I've made and, since I am far away from being knowledged in maths, I really don't know if they are correct. So I'd be very thankful if you could review this and tell me if what I've said it's correct or not, and in case it's not explain me why.

Take in consideration that I don't know how to operate with vectors in 3D and only know to add and substract vectors and to work with right angle main trigonometric functions (sin, cos, tg, arcsin, arccos, arctg), so if you had to give me some advice it would be easier for me if you could do it with tools that don't need to imply knowledge in the above things I stated I don't know at the moment -hope I'll learn them soon though.

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π°︎ r/learnmath
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π€︎ u/susurubi
π︎ Jun 26 2020
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Need help with these questions, trigonometry, unit circle, determining local extremes, etc.

1) In the figure you see a unit circle with the angle v and the point p marked. Which coordinates have a point on the circle with the angle = (v - 90) degrees?

2) Determine local extremes for f(x) = |2x-1| when 0β€xβ€2.

3) Describe what is meant by a proof of contradiction, and what is meant by an asymptote.

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π€︎ u/mogsuru
π︎ Jul 31 2020
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[Basic trigonometry] If I know the value of "C" and the radius of the circle, how can I calculate "A"?

Here's the example ->

https://i.imgur.com/th2VXq9.png

Let's say I know the value of "c" (the red arc length) and I need to calculate "a" (the blue portion of the tangent) in order to be able to finally calculate "b" (the green line).

How can I do it? I am aware that this is a very basic concept in trigonometry yet I forgot it so I would be thankful if you could explain me this one.-

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π€︎ u/susurubi
π︎ Apr 29 2020
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What type of situations do people use the unit circle in trigonometry?

Hello everyone. I have been relearning trigonometry on Khan Academy because it has become relevant in my working life. One of the interesting things is that I have more appreciation for things I thought were pointless in school (because now I know they have applications). However, I'm struggling with what practical ways we can use the unit circle. I see that it's a good way to prove the relationship between sine, cosine, tangent, etc. But are there situations in working life where someone would want to use the unit circle?

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π︎ Mar 26 2020
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[Trigonometry] Points along a circle

Hi all,

I am developing a game, and some math is required. Normally I would google this but I have no clue what to look for in this case. I think this will be a piece of cake for everyone here, so please help me!

I have a player, the most important thing about him is his center, which is the origin point. Around the origin point is an imaginary circle with a known radius. The cursor is the only other known point to which I draw a line. I want to draw two (imaginary) lines both 22.5 degrees from the cursor point/line.

The length of all three lines (the one to the cursor, the one to the counterclockwise point and the one to the clockwise point) are the known radius.

What is the formula to get the clockwise and counterclockwise points along that circle?

Wouter

(a desperate not so mathematician)

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π€︎ u/Captain_Infinite
π︎ Apr 03 2020
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[High school trigonometry:unit circles] help with non sin. or cos. functions?
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π€︎ u/s-swan
π︎ Apr 29 2020
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Trigonometry Circle Question

Sorry for the title not being that specific. I'm not sure how to explain this problem.

Here is the math problem. I've no idea how to even approach it. I'm not looking for an answer, just some help understanding how to approach and solve it. Cheers!

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π°︎ r/trigonometry
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π︎ Feb 03 2020
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The Unit Circle is most important tool in Trigonometry, in my opinion. Better than Special Triangles.
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π︎ Nov 03 2019
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[Trigonometry/Geometry] The diagram on the left shows a chord AB and its central angle β AOB = ΞΈ. Suppose the diameter of the circle is 1. How is the length of AB related to ΞΈ?

The problem.

They give the answer as sin(ΞΈ/2), but I'm not sure how they got to that.

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π︎ Mar 12 2020
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How come trigonometry doesn't involve other shapes besides a circle?

Like, why not use a triangle or a square? Is it because there is no use for those types of functions?

Also, is there literature on this type of thing?

Edit: I know triangles are involved by projecting them on a unit circle. I'm wondering why the unit shape is a circle and why other shapes don't have a use.

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π€︎ u/CuriousConstant
π︎ Oct 21 2019
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[College Trigonometry] Unit Circle Problem: How do I explain why?
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π€︎ u/Bretherman
π︎ Nov 14 2019
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[GCE O levels: Circles, trigonometry]How do you find the area of the quadrilateral , the ans is 19cm^2
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π€︎ u/iLiekDreaming
π︎ Oct 16 2019
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When you have to draw a unit circle for trigonometry
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π°︎ r/raimimemes
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π︎ Sep 01 2019
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Quadratic, Complex numbers, Parabolas, Circles, Domain and Range, Functions, Trigonometry challenge problems?

Where can I find quadratic challenge problems, complex numbers challenge problems, parabolas challenge problems, domain and range challenge problems, function challenge problems, and trig challenge problems? The purpose is to practice my ability to solve challenge problems in these topics.

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π°︎ r/MathHelp
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π︎ Mar 20 2021
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Quadratic, Complex numbers, Parabolas, Circles, Domain and Range, Functions, Trigonometry challenge problems?

Where can I find quadratic challenge problems, complex numbers challenge problems, parabolas challenge problems, domain and range challenge problems, function challenge problems, and trig challenge problems? The purpose is to practice my ability to solve challenge problems in these topics.

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π︎ Mar 20 2021
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Quadratic, Complex numbers, Parabolas, Circles, Domain and Range, Functions, Trigonometry challenge problems?

Where can I find quadratic challenge problems, complex numbers challenge problems, parabolas challenge problems, domain and range challenge problems, function challenge problems, and trig challenge problems? The purpose is to practice my ability to solve challenge problems in these topics.

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π°︎ r/mathstudents
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π︎ Mar 20 2021
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