Placeholder Image

字幕表 動画を再生する

  • - [Instructor] We are asked,

  • what is the slope of the line that contains these points?

  • So pause this video and see if you can work through this

  • on your own before we do it together.

  • Alright, now let's do it together,

  • and let's just remind ourselves what slope is.

  • Slope is equal to change in y,

  • this is the Greek letter delta,

  • look likes a triangle,

  • but it's shorthand for change in y

  • over change in x.

  • Sometimes you would see it written as y2 minus y1

  • over x2 minus x1

  • where you could kind of view x1 y1 as the starting point

  • and x2 y2 as the ending point.

  • So let's just pick two xy pairs here,

  • and we can actually pick any two

  • if we can assume that this is actually describing a line.

  • So we might as well just pick the first two.

  • So let's say that's our starting point

  • and that's our finishing point.

  • So what is our change in x here?

  • So we're going from two to three,

  • so our change in x is equal to three minus two

  • which is equal to one,

  • and you can see that to go from two to three

  • you're just adding one.

  • And what's our change in y?

  • Our change in y is our finishing y one

  • minus our starting y four, which is equal to negative three.

  • And you could of, you didn't even have to do this math,

  • you would have been able to see

  • to go from two to three you added one,

  • and to go from four to one, you have to subtract three.

  • For there we have all the information we need.

  • What is change in y over change in x?

  • Well, it's going to be,

  • our change in y is negative three

  • and our change in x is one.

  • So our slope is negative three divided by one

  • is negative three.

  • Let's do another example.

  • Here we are asked, what is the slope

  • of the line that contains these points?

  • So pause this video and see if you can figure it out

  • or pause the video again and see if you can figure it out.

  • Alright, so remember, slope is equal to change in y

  • over change in x.

  • And we should be able to pick any two of these pairs

  • in order to figure that out if we assume

  • that this is indeed a line.

  • Well, just for variety, let's pick these middle two pairs.

  • So what's our change in x?

  • To go from one to five, we added four.

  • And what's our change in y?

  • To go from seven to 13, we added six.

  • So our change in y is six when our change in x is four.

  • And I got the signs right, in both case it's a positive.

  • When x increases, y increased as well.

  • So our slope is six fourths,

  • and we could rewrite that if we like.

  • Both six and four are divisible by two,

  • so let be divide both the numerator and the denominator

  • by two and we get three halves, and we're done.

- [Instructor] We are asked,

字幕と単語

ワンタップで英和辞典検索 単語をクリックすると、意味が表示されます

A2 初級

表から傾きを計算する|線形方程式とグラフ|代数I|カーンアカデミー (Calculating slope from tables | Linear equations & graphs | Algebra I | Khan Academy)

  • 6 0
    林宜悉 に公開 2021 年 01 月 14 日
動画の中の単語