Refleksi video 2

Reflection of English Lecture

Another Way to Study English with Video Approching

          Monday, March  25^th  2013 we meet again with Mr.Marsigit. In this meeting He showed us again about mathematical content in video. I think his videos are interesting, because we could learn english with another way, likes from matematical content, from movie, and from speech. And I can catch from the meeting is we must study english, because english is language, and language is live, so we must applied it in our live.And Then, there is the reflection from this videos.

             Mr. Marsigit showed us seven videos. With the title are :

1. Quadratic Form

2. Inequality

3. Graph Intersec

4. Belive in me

5. Dead poet

6. Solving differential equation

7. Invers function

First, video 1. The title is quadratic form, the main idea from this video is about what is quadratic form and there are specification.

There is function like this : Three X minus 1 multiply X plus two equals to three X square plus 6 X minus X minus one, equals to Three square plus 5 X minus two. (its basic quad form a quadratic equation. So we ger the function y equals to three X square plus 5 X minus two an its call standard form for a quadratic equation.

So we get the standart form for a quadratic equation is :

y = ax² + bx + c

y is equals to a X square plus b X plus c. a is coeffisient of X square, b is coeffisient of X, and c is constant. And quadratic equation differen with linear equation, but it can from multiply the linear equation. In the linear equation the standard form is : y = mx + b, in this case b has no X and m is the coeficient of x. 

When some think fall down to the ground from the hight, 100. So the equation is

y = 100 – 16 x². Y equals to one hundred minus 16 X square.from the function we know the position, there are :

at x is equals 0 the value of y is 100,  from the equation y = 100 minus 16 multiply 0 square is 100.

At x is equals 1 the value of y is 84, from the equation y = 100 minus 16 multiply 1 square is 100 minus 16 = 84.

At x is equals 2 the value of y is 36, from the equation y = 100 minus 16 multiply 2 square is 100- 16 multiply 4 is 100 – 64 = 36.

On average, from 100 hight, is fall in 16 feet/second. And from (1,84) to (2,36) it fall in 48 feet/second. It cange because the time is changes. And from the curve we can know that the curve build or consist from many point, and the graft not straight, but curve.

And the original the graph of it is parabola.

the example of graph of parabola are:

1. Water fire.
2. Smile
3. The bright.

Second, video 2. The title of the video is Inequality. The main ide of  This video is tells us the definition of inequality and the example.

Inequatity is an expression that is unbalanced. The example is 5 > 3, 4 < 7.

The other example is when we play seesaw with friend, that the weights are equal so the cart is straight, and when your friend move from the side, so your weight is greather than the weight on the other side. And then, when your frind in the other side is big bruce, so the cart is unbalance again, its means that your weight is less than big bruce`s.

The symbol “ < ” is calls less than, and when the somethink show like this 3 < 5 it’s means that 3 is less than 5, and the other symbol is ‘ ∟’. Examples 2∟7, it’s means that 2 is less than 7.

The symbol “ > ” is calls greater than, and when the stetement show like 6 > 2, it’s means that 6 is greater than 2. Just like 9 > 8.

The symbols are likes the mounth hungry of dinosaur. When the mouth is up is be greater than, and the side when the mouth is cute so the number in the side is less than other side.

Third, video 3. The title of the video is  Graph Intersec. This video tells us the definition of the parallely.

When we know there is two line in the graph intersec. And its posible that two lines never meet. The example is when bob is walking on the mill avenue, and david is walking on spruce street, and they not be meet and cross, so it’s parallel to each. It’s parallel lines.

Next, video 4. The title is Belive in me. The video is different with other video, because the video is learn we two point the first is motivation, and another is we can lern the english language from this.

The first, there is a boy who was speech on the stand. And the audiant is ledies and gentle man and I think they were a teacher or parents. The names is Dalton Sherman, from the school, first he ask to the audient “ Do you belive in me?”, I think from the video I can lern that if the young learners say need to the teacher, it’s good. Young learners say that mathematics is beautiful from they own, not the old teacher that say it. And everythink is need trust. The teacher trust to the toung learners that can handle they ability, and Young learners trust to teacher that can facilitate them. Because trust is sunnatullah.

And the summary of dalton speech there are :

Dalton say “I belive in me, do you belive in me?, do you belive that I can stand up here and talk of twenty thousand of you?”. From the sentence, I can conclude that Dalton Sherman is the student whose confidently stand up in stage and speech to twenty thousand audience and Dalton Sherman make convincing audience that he can stand up in stage and can handle him live. Because the real he can do anything, can be anything, dream anything, and become anything. And he say that teacher must belive that young learners have rich potential. 

Not only this, but also we can learn english structure from Dalton Sherman say. Likes do you belive in me ?. ‘in’ is the spouse with belive. Not it, on, or over.

            Then, video 5. The title is Dead poet. This video is short movie that tells us about important to looking for our way. In this case, the setting is on the classroom there are teacher and students. From the video I can conclude that we can look anythink from yhe other side. We can looking for our way with different way. And we must try in order to get your english.

Video 6. The title is Solving differential equation. The main idea of this video is about differential equation. Find y=f(x) satisfies the equation for all values of x and y. Solve for the dependent variable, usually y. First, Integrate (just like we didi in calculus).

Example : dy equals to 4 x square dx. So become dy over dx equals to 4x². And then, we integrate become intergate of dy over dx and in the right side we get integrate of 4x². Trying to get dependent variable, y, all by it self. So become inthe left side is dy over dx multiply dx, and in the right side is 4x² multiply dx. In the left side dx and dx is canceled out. So we get dy = 4x² dx.  So we integrate this equation in the left side integrate dy equals to integrate 4x² dx. So we get y = 4/3 x³ + C, C is constant and represent the infinite family of solution curves for the equation.

Last video, video 7. The title is Invers function. This video is the education video, in this video there is teacher who explain about invers function.

When the function if F(x,y)=0. So its represent the function y=f(x). So we can have another function x=g(y). In this y=f(x) is vertical line and x=g(y) is call horizontal line. If we have the function is y = x²
So the function is invertible. If we have y = 2x -1.  
so we have two function. We can substitute the function, so the expresion is : x equals to 2x minus 1. All side we plus 1. So became 1 + x equals to 2x. So we solve the equation and we get x = 1. It’s the position of cross. And we solve the equation to ger the invers. 2x – 1 equals y. So 2x = y + 1, and then we divede all side  with 2. So we get x = ½(y+1). Or y = ½ y + ½. So the invers is x we change to y. And y change became x. So y = ½ x +1/2.

So the invers line is have same point meet. Likes graph. We can solve with algebra. F(x) = 2x -1. And the g(x) = ½ x + ½. We add the g(x) to f(x). So f(g(x)) = 2 [..something...] -1, [.....] we add the g(x) function. So f(g(x)) = 2 [1/2x-1/2] -1 equals to x + 1 – 1 = x.

                    And vice versa, We add the f(x) to g(x). G(f(x)) equals to ½[.....] +1/2. And we add f(x) function. We get ½[2x-1] + ½ equals to x – ½ +1/2 + also we get x. So the important that g = f^-1. F(g(x)) = f(f^-1(x)) equals to x, and g(f(x)) = f^-1(f(x)) also equals to x.

                    So we check with the example. y =  x-1 over x + 2.

               So we can solve, y(x+2) equls x-1. So we heve yx + 2y equals x-1. And we simplify yx-x equals -1 – 2y. So we have (y-1)x = -1 -2y. an ve devide all side with (y-1) so we get. X = -1 – 2y over y -1. So we change x become y, and x become y. we get y = -1-2x over x-1. If we add x = 0, we get y= -1. And we add y = 0, we get -1 -2x = 0. -2x = 1. X = -1/2.

So the last are, if we have the function y = 2^x, and the invers is y = log₂ x.