“ REFLECTION 1 ”
By : Elsa Winda Prastiana
09313244015

At March 19th 2012, Mr.Marsigit showed some videos about mathematical content. That videos purpose to employ VTR to learn English for Mathematics Education. In video 1, we learn about derivative notation.  We know that notation for derivative is f’(x) is read f prime of x. We also can say y’, because f (x) and y are interchangeable. Finally, we get dy/dx . Key word in derivative is slope of tangent line at point. We can get slope of a line = (y2-y1)/(x2-x1). From the definition of derivative, we get f'(x)=lim(h→0) (f(x+h)-f(x))/h. Derivative just not limit of a slope it is also limit change in values of f(x) over change in x or instantaneous rate of change.

In the next video, we learn about angle. Angle is made up of two rays connected at the same point. First ray drawn to form an angle is called initial side. Second ray drawn to form an angle is called terminal side. Vertex is point where initial and terminal sides meet. Two ways to measure an angle :
1. By the direction terminal side goes in
    If terminal side rotates in counter clockwise direction then positive angle.
    If terminal side rotates in clockwise direction then negative angle.
2. How far the terminal side rotates from the initial side
When measuring an angle we want both the initial and terminal sides on top of one another on x-axis, vertex of two rays at the origin of graph. When an angle’s vertex is at origin of graph and initial side is on positive x-axis the angle is in standard position. X-axis is positive on right side of y-axis and negative on other side but y-axis is positive above x-axis and negative below it.
Two measure an angle in radian and degrees.
   
From the third video, we learn about Trigonometry. Trigonometry is arranged from triangle and meter. From the triangle, we can get about sinus, cosinus and tangent. The formula of Sinus is opposite/hypotenus , Cosinus is adjacent/hypotenus and Tangent is opposite/adjacent. Usually, we can remember it by acronym SOH CAH TOA. In the next video, we learn about inverse function. From this video, we know how to get inverse from a function and how we sketch the graph. Then, in next video we learn about integer. Integer numbers is whole numbers and their negatives. Integer numbers can divide be 3 kinds. First, positive numbers. The second is zero and the third is negative numbers. In the sixth video, we study about factoring polynomials. How we can factorize the polynomial.