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The Math District
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Добавлен 26 ноя 2017
Welcome to The Math District!
I teach college math classes in the United States, and I have created this channel to provide easy to follow videos on a large variety of math topics.
I hope you will learn a lot! Thank you for watching.
I teach college math classes in the United States, and I have created this channel to provide easy to follow videos on a large variety of math topics.
I hope you will learn a lot! Thank you for watching.
What Are the Real Numbers?
Explaining the Natural Numbers, the Whole Numbers, the Integers, the Rational Numbers, the Irrational Numbers, and the Real Numbers with examples.
Просмотров: 127
Видео
The Power Rule with Examples
Просмотров 5018 часов назад
Learn how to apply the power rule with these 6 examples.
The Power Rule d/dx(x^n)=nx^(n-1). Proof Using the Definition of Derivatives.
Просмотров 56823 часа назад
Learn how to use the Definition of the Derivative Function to prove the Power Rule.
Calculus: The Constant Rule d/dx(c)=0 - Graph, Proof, and Examples
Просмотров 79День назад
Learn about the derivative of the constant function f(x)=c.
In the Quadrilateral ABCD Find Angle X
Просмотров 465День назад
Learn now to divide the quadrilateral into triangles and find angle X.
What is the Area of the Yellow Region?
Просмотров 772День назад
Given two concentric quarter-circles, learn how to find the area of the yellow region.
Intersection and Union of Sets
Просмотров 5814 дней назад
Learn about intersection, union, Venn Diagrams, and empty sets.
Three Methods for Describing a Set is Mathematics
Просмотров 8714 дней назад
Learn about the Roster Method, the Set-Builder Notation, and the Word Description Method.
Find the Area of the Equilateral Triangle.
Просмотров 1,2 тыс.14 дней назад
Given the radius of a semicircle inscribed in an equilateral triangle, find the area of the triangle.
Given the Equation (Formula) 4/z-5/x=1/y, Solve for x.
Просмотров 21121 день назад
Learn how to solve a formula that has fractions for a certain variable.
The 4 Derivative Notations: Lagrange's, Leibniz's, Newton's, and Euler's
Просмотров 61621 день назад
Learn about the main four notations for differentiation.
Given radius of a quarter-circle is 20 units, what is the area of the yellow region?
Просмотров 701Месяц назад
Given a quarter circle and two semicircles, learn how to use geometry to find the area of the yellow region.
Can You Recognize These 15 Math Formulas?
Просмотров 822Месяц назад
Refresh you Algebra and Geometry skills.
Calculus: What is a Derivative? Simple Explanation with an Example
Просмотров 204Месяц назад
Learn how to derive the formula for the derivative function, and see the geometric interpretation through an example.
Can You Find Angle x?
Просмотров 237Месяц назад
Learn how to work with isosceles triangles to find missing angles.
What Is a Formula and How Many Variables It Can Have?
Просмотров 73Месяц назад
What Is a Formula and How Many Variables It Can Have?
Find the Area of the Green Rectangle Inscribed in a Right Triangle.
Просмотров 643Месяц назад
Find the Area of the Green Rectangle Inscribed in a Right Triangle.
Evaluate the Algebraic Expression 2(x^4+9x)^3-5x for x=-2.
Просмотров 120Месяц назад
Evaluate the Algebraic Expression 2(x^4 9x)^3-5x for x=-2.
Exponential Notation - A Beginner's Guide + Practice
Просмотров 76Месяц назад
Exponential Notation - A Beginner's Guide Practice
Geometry Challenge - Find the Side of the Blue Square.
Просмотров 1,3 тыс.Месяц назад
Geometry Challenge - Find the Side of the Blue Square.
Algebraic Expressions vs Equations - What’s the Difference?
Просмотров 1262 месяца назад
Algebraic Expressions vs Equations - What’s the Difference?
12 Must-Know Topics Before Taking Your First Calculus Class
Просмотров 1122 месяца назад
12 Must-Know Topics Before Taking Your First Calculus Class
The Importance of the lim(x→0)(sinx/x)=1 and Its Geometric Proof
Просмотров 8173 месяца назад
The Importance of the lim(x→0)(sinx/x)=1 and Its Geometric Proof
d/dx(sin(x)) = cos(x). The Proof Using the Definition of the Derivative of a Function.
Просмотров 6113 месяца назад
d/dx(sin(x)) = cos(x). The Proof Using the Definition of the Derivative of a Function.
What are the measures of angles C and D? Full Explanation.
Просмотров 2573 месяца назад
What are the measures of angles C and D? Full Explanation.
How to Find the Derivative of f(x)=x^(1/3) Using the Definition of a Derivative Function
Просмотров 3353 месяца назад
How to Find the Derivative of f(x)=x^(1/3) Using the Definition of a Derivative Function
What is a Tangent Line? Can a Tangent Line Cross a Curve at the Point of Tangency?
Просмотров 1684 месяца назад
What is a Tangent Line? Can a Tangent Line Cross a Curve at the Point of Tangency?
Find Angle x. Think Outside the Box with This Geometry Challenge.
Просмотров 2714 месяца назад
Find Angle x. Think Outside the Box with This Geometry Challenge.
and how do you find the perimeter?
Thank you
Wow ty so much
You’re welcome! 😊
Great illustrations and explanation 😄
Thanks! I'm glad you found them helpful.
Longer way with trig: Drop a perpendicular from C to AB, call intersection point E. △CEB is 30-60-90, so EB = AE = 2 and EC = 2√3 Perpendicular from AD to C, call it F. FC = AE = 2 DF = 4 - 2√3 x = tan⁻¹(FC/DF) = tan⁻¹(2/(4 - 2√3)) = tan⁻¹(2 + √3) = 75°
Easy explanation, thank you!
Glad it was helpful!
Thankyou 🙏
You’re welcome 😊
I used my excel formula, encoding only 3 sides measurement and l get the same result for radius.
Thanks for appreciating my method.
Solution: s = side of the equilateral triangle, P = right point of contact from the semicircle to the equilateral triangle. OCP is the famous triangle with the angles 30°, 60° and 90°. The hypotenuse is OC = s/2 and the short leg is s/4 and the long leg is: √[(s/2)²-(s/4)²] = r = 10 |()² ⟹ s²/4-s²/16 = 100 ⟹ 4s²/16-s²/16 = 100 ⟹ 3s²/16 = 100 |*16/3 ⟹ s² = 100*16/3 ⟹ area of the equilateral triangle = 1/2*s*√[s²-(s/2)²] = 1/2*s*s/2*√3 = 1/4*s²*√3 = 1/4*100*16/3*√3 = 400*√3/3 ≈ 230,9401
Amazing! Thank you for sharing this method.
i love this video, it's very simple and helpfull
Thank you, I really appreciate your comment.
4/z-5/x=1/y is just an arbitrary equation, not a formula. While all mathematical formulas are equations, not all equations are formulas. A (mathematical) formula is an equation that expresses a principle. For example: E = mc**2 is a formula that expresses the principal of mass-energy equivalence. V = IR is a formula that expresses Ohm's law. Consider taking a refresher course in basic English.
Consider not using RUclips comments to feel better about your low self esteem. You’ve never learned another language because it’s too hard for you. Bye ❤
Consider not being r*cist. You’ve never leaned another language because it’s too hard for you. I hope middle school goes well ❤
@@lucasw158 I completed 4 years AP French in high school and a year of German at the university where I earned my degree in math, you fool.
@@lucasw158 I completed 4 years of AP French in high school and a year of German at the university where I earned my degree in math. It's not being racist to observe that 4/z-5/x=1/y is an equation, not a formula, even in the language of the narrator of this video. The person simply doesn't know the difference between an equation and a formula. Apparently, even you don't know the difference.
A formula is an equation that has two or more variables, so this equation counts as a formula.
Thank you very much. very good explanation.
Thank you, I am glad it was helpful!
Very useful video - thanks
Nice explanation. Thanks
Thank you!
Merry Christmas
Merry Christmas to you too!
I have find your videos by chance I get found of it thanks alot for your simplicity the math is my hoppy
Thanks for watching! I'm happy you're finding the math helpful.
Thanks from Morocco
You are very welcome!
شكرا األك
❤❤❤ Thank you thank you thank you so much 😊❤
You are so welcome!
You are the best teacher I have ever seen ❤️🥰 lots of love 😘
Thank you so much for the kind words, I really appreciate it!
I'm trying to study for my final and have always struggled with this concept, but this is the easiest-to-understand video I've ever seen. Thank you so much!
I'm so glad it helped you! I wish you the best on your final.
[180-[[(180-25)/2]-25]]/2=63,75°
Oh fux, I started trying to "asking Pythagoras", but got no answer! Thanks for a less complex response.
Can you find answer for the value of radius equal to 7 cm😢
Thank you
Awesome! Thanks for the simple explanation!
Simple explanation and nicely put 🤔💭🧮
Thanks for watching!
so there is a equation to find radius of incircle, Area of triangle/half of the perimeter of triangle
They're obviously all 345 triangles so all the angles are given. Move on...
Wow great explanations, I thought even and odd was hard until i saw this video, this help me a lot thank you
I'm glad you found the video helpful and I really appreciate your comment. Thank you.
This was interesting, thanks for teaching!
I'm happy to hear you enjoyed it.
Lado del cuadrado =c---> 3=(5c/4)+(3c/5)---> c=60/37. Gracias y saludos
Really awesome explanation, thank you!!
You're very welcome!
Awesome! Thanks for another great math video!
Glad you liked it!
I used cosine rule to calculate the angle ACB = 71.8 degree. Let a = distance of C to the point P, the tangent of line BC to the circle. b = distance of B to the point Q, the tangent of line BC to the circle, c = distance of A to the point R, the tangent of line AC to the circle. Given that the line CO (center of the circle) bisects the angle of ACB, BO bisects angle CBA and AO bisects angle CAB, I got a = 3.5, b = 5.5 and c = 4.5. Angle OCP = 71.8 / 2 = 35.9 degrees. The radius r = a x tan 35.9 = 3.5 x 0.7237 = 2.53 units
I study for te exams, this is a big help, thank you
Happy to help!
Method 3 and 4 are easy to apply
I agree! They are both very efficient methods.
Great proof, but why is this important?
thank you for this! i have been struggling about understanding transformations and you explained this very well. i hope this channel gain more viewers, your videos are very helpful.
Thank you so much for the kind words! I really appreciate it.
Iam very glad... best teacher
I really appreciate that, thank you!
Maestra, gracias por su ayuda, soy un pobre latino indefenso en busca del sueño americano, pero el álgebra me impide alcanzar mi sueño de ser alguien en la vida, confío en que gracias a su tutorial, pueda salir de este gran problema que me está carcomiendo el alma, y logre grandes cosas al igual que usted, es un honor ver este vídeo sin morir en el intento, gracias una vez más.
40^2-36^2+4^2=72x-8x=64x X=(4*76+16)/64=(76+4)/16=80/16=5 Height =X+4=5+4=9
Great illustrations, thanks for explaining!
You're very welcome! I'm glad you found the illustrations helpful.
Brilliant
You are a great teacher. Thank you so much.
I appreciate that, thank you!
Let's solve this in an entirely general way. We can describe the problem as follows. (1) Impose a standard x/y coordinate system on the problem (2) Rectangle dimensions: width w, height h (3) Rectangle corners: (0, 0), (w, 0), (w, h), (0, h) (4) Target triangle corners: (u, 0), (w, h), (0, v) (5) Area of triangle (0, 0), (u, 0), (0, v): X (6) Area of triangle (0, v), (w, h), (0, v): Y (7) Area of triangle (u, 0), (w, 0), (w, h): Z (8) Area of triangle (u, 0), (w, h), (0, v): a (this is the variable we seek) (9) Define S = X + Y + Z Note that we have used uppercase variables for quantities that are "given" and lower case for quantities that we do not know. So our ultimate goal is to get an expression for a that is in terms of uppercase variables only. We can immediately write the following four relationships: (10) w*h = a + S (11) u*v = 2*X (12) (w-u)*h = 2*Y (13) w*(h-v) = 2*Z This is simple, but as a linear system it has five unknowns: w*h, a, u*v, u*h, and w*v, but there are only four equations. This tells us immediately that no amount of linear algebra will get us to the solution we seek. We have to do something nonlinear. First, expand equations (12) and (13): (14) w*h - u*h = 2*Y (15) w*h - w*v = 2*Z Now form the sum and product (14)*(15) and substitute (10). The product is our nonlinear action: (16) 2*w*h - (w*v + u*h) = 2*Y + 2*Z (17) -(w*v + u*h) = 2*Y + 2*Z - 2*(S + a) (18) (w*h)*(w*h) - (w*h)*(w*v) - (u*h)*(w*h) + (u*h)*(w*v) = (2*Y)*(2*Z) Substitute in (10), (11), and (17): (19) (a + S)^2 - (a+S)*(w*v) - (a+S)*(u*h) + (a+S)*(2*X) = (2*Y)*(2*Z) (20) (a + S)^2 + (2*X - (w*v + u*h))*(a+S) = 4*Y*Z (21) (a+S)^2 + (2*X + 2*Y + 2*Z - 2*S - 2*a)*(a+S) = 4*Y*Z (22) (a + S)^2 - 2*a*(a + S) = 4*Y*Z Finally just expand and simplify: (23) a^2 + 2*S*a + S^2 - 2*a^2 - 2*S*a = 4*Y*Z (24) -a^2 + S^2 = 4*Y*Z (25) a^2 = S^2 - 4*Y*Z (26) a = sqrt(S^2 - 4*Y*Z) This is our final answer. One might ask why Y and Z appear explicitly while X does not, but if you look at the original diagram you see that X is "special" in the sense that it is the only triangle with a corner at the origin. Note that we can always rotate any problem of this type to bring it into this form - to ensure that only one of the four triangles has a corner at the origin. I'm sure it could be solved in any orientation, but as I've played with this a few times I've felt like the algebra is simplified by putting it into this "standard orientation." Finally, we note that this does give the right answer. For our given problem we have S = 54, Y = 15, Z = 27. If you plug those in you do get 36.
Molto bello❤