Log in Anish Mantri 8 years agoPosted 8 years ago. Direct link to Anish Mantri's post “What would I write if the...” What would I write if the function has arrows at the end of the line on both sides? • (31 votes) Patrick 8 years agoPosted 8 years ago. Direct link to Patrick's post “The arrows simply mean th...” The arrows simply mean that the function goes on forever. (40 votes) Annei Titania 6 years agoPosted 6 years ago. Direct link to Annei Titania's post “How do you find the domai...” How do you find the domain of a parabola? Do you use the same process? • (16 votes) David Severin 6 years agoPosted 6 years ago. Direct link to David Severin's post “A parabola should have a ...” A parabola should have a domain of all real numbers unless it is cut off and limited. Both the left side and the right side normally have arrows which mean it will go on forever to the left and forever to the right. (9 votes) creslos2 a year agoPosted a year ago. Direct link to creslos2's post “So essentially we can int...” So essentially we can interpret this as Domain being represented along the X-axis and Range along the Y-axis? • (9 votes) 12ikerzhong 7 months agoPosted 7 months ago. Direct link to 12ikerzhong's post “yes Domain is the X axis ...” yes Domain is the X axis and range is the Y axis (3 votes) Kayley 6 years agoPosted 6 years ago. Direct link to Kayley's post “I'm confused on what sign...” I'm confused on what signs to use (greater than equal to, less than equal to, etc) I know that you use the greater than equal to and less than equal to, when it's included, but how do you know what sign to use when graphing? How do you know which way the graph is going? I'm not sure if I am making sense • (8 votes) David Severin 6 years agoPosted 6 years ago. Direct link to David Severin's post “The "equal" part of the i...” The "equal" part of the inequalities matches the line or curve of the function, so it would be solid just as if the inequality were not there. Without the "equal" part of the inequality, the line or curve does not count, so we draw it as a dashed line rather than a solid line (6 votes) 000ghostlyvenom 2 years agoPosted 2 years ago. Direct link to 000ghostlyvenom's post “-2<x<5 how can i write th...” -2<x<5 how can i write the inequalities? • (4 votes) Kim Seidel 2 years agoPosted 2 years ago. Direct link to Kim Seidel's post “You would write your ineq...” You would write your inequality in interval notation as: If the inequality is: -2≤x≤5, then the interval notation is: If you have an inequality like: -2≤x<5, then the interval notation is: Hope this helps. (13 votes) Lisa Barua 5 years agoPosted 5 years ago. Direct link to Lisa Barua's post “What is a function?I ke...” What is a function? I keep confusing myself on what it is... • (5 votes) Ms. McWilliams 5 years agoPosted 5 years ago. Direct link to Ms. McWilliams's post “A function is a relation ...” A function is a relation where every domain (x) value maps to only one range (y) value. If you have the points (2, -3), (4, 6), (-1, 8), and (3, 7), that relation would be a function because there is only one y-value for each x. X-values don't repeat. If you have the points (2, -3), (4, 6), (2, 8), and (3, 7), that relation would not be a function because 2 for the x-value repeats, meaning 2 maps to more than one y-value. Repeating x-values mean the relation is not a function. You might want to check out https://www.khanacademy.org/math/algebra/algebra-functions/evaluating-functions/v/what-is-a-function (7 votes) Милена ฅʕ•̫͡•ʔฅ a year agoPosted a year ago. Direct link to Милена ฅʕ•̫͡•ʔฅ's post “If we have f(x)=(1/3)^x, ...” If we have f(x)=(1/3)^x, we can see that it approaches 0, but never touches it. Does that mean that the range is (∞,0)? • (4 votes) Kim Seidel a year agoPosted a year ago. Direct link to Kim Seidel's post “Yes, but you should alway...” Yes, but you should always right the range in numeric order: (0,∞). (7 votes) sirionna 9 months agoPosted 9 months ago. Direct link to sirionna's post “so for the domain you don...” so for the domain you dont need the greatest point the line touches in the graph, but you need that for the range..? i need clarification please • (5 votes) Kim Seidel 9 months agoPosted 9 months ago. Direct link to Kim Seidel's post “Domain is all the values ...” Domain is all the values of X on the graph. So, you need to look how far to the left and right the graph will go. There can be very large values for X to the right. Range is all the values of Y on the graph. So, you look at how low and how high the graph goes. Hope this helps. (4 votes) s28798726 10 months agoPosted 10 months ago. Direct link to s28798726's post “how high is up” how high is up • (6 votes) 29kaushika 5 months agoPosted 5 months ago. Direct link to 29kaushika's post “What website is Sal using...” What website is Sal using for these questions? • (4 votes) Speedyspeedcuber a month agoPosted a month ago. Direct link to Speedyspeedcuber's post “Sal is using Khan academy...” Sal is using Khan academy, but since this video was recorded a while ago, it looks different from the Khan academy that we use today. (4 votes)Want to join the conversation?
The < or > has to do with the shading of the graph, if it is >, shading is above the line, and < shading is below. The exception is a vertical line (x = #) where there is no above and below, so it changes to the left (<) or to the right (>)..
So lets say you have an equation y > 2x + 3 and you have graphed it and shaded. If you try points such as (0,0) and substitute in for x and y, you get 0 > 3 which is a false statement, and if you did it right, shading would not go through this point. If point is (1,5) you can do the same thing, 5 > 5, but this would be right on the line, so the line would have to be dashed because this statement is not true either. One more point (0,6) would give 6>3 which is a true statement, and shading should include this point.
Does this answer your question?
(-2, 5)
The parentheses tell you that the inequalities do not include the end values of -2 and 5.
[-2, 5]
The square brackets tells you that the end values are included in the interval.
[-2, 5)
A square bracket is on the -2 because it is included in the interval. The 5 gets a parentheses because it is not in the interval.
I know domain is x and range is y
No repeating x-values mean the relation is a function.
Video transcript
The function f of x is graphed. What is its domain? So the way it's graphedright over here, we could assume that thisis the entire function definition for f of x. So for example, ifwe say, well, what does f of x equal when xis equal to negative 9? Well, we go up here. We don't see it's graphed here. It's not defined for xequals negative 9 or x equals negative 8 and 1/2 orx equals negative 8. It's not defined forany of these values. It only starts getting definedat x equals negative 6. At x equals negative 6,f of x is equal to 5. And then it keepsgetting defined. f of x is defined for x allthe way from x equals negative 6 all theway to x equals 7. When x equals 7, fof x is equal to 5. You can take any x valuebetween negative 6, including negative6, and positive 7, including positive7, and you just have to see-- youjust have to move up above that number,wherever you are, to find out what the value ofthe function is at that point. So the domain of thisfunction definition? Well, f of x isdefined for any x that is greater than orequal to negative 6. Or we could say negative 6is less than or equal to x, which is less thanor equal to 7. If x satisfies thiscondition right over here, the function is defined. So that's its domain. So let's check our answer. Let's do a few more of these. The function f of x is graphed. What is its domain? Well, exact similar argument. This function is not definedfor x is negative 9, negative 8, all the way down or all the wayup I should say to negative 1. At negative 1, itstarts getting defined. f of negative 1 is negative 5. So it's defined for negative1 is less than or equal to x. And it's defined all theway up to x equals 7, including x equals 7. So this right overhere, negative 1 is less than or equal to xis less than or equal to 7, the function isdefined for any x that satisfies this doubleinequality right over here. Let's do a few more. The function f of x is graphed. What is its range? So now, we're notthinking about the x's for which thisfunction is defined. We're thinking aboutthe set of y values. Where do all of they values fall into? Well, let's see. The lowest possible y valueor the lowest possible value of f of x that we gethere looks like it's 0. The function never goes below 0. So f of x-- so 0 is lessthan or equal to f of x. It does equal 0 right overhere. f of negative 4 is 0. And then the highest yvalue or the highest value that f of x obtains in thisfunction definition is 8. f of 7 is 8. It never gets above 8, but itdoes equal 8 right over here when x is equal to 7. So 0 is less than f of x, whichis less than or equal to 8. So that's its range. Let's do a few more. This is kind of fun. The function f of x is graphed. What is its domain? So once again, this functionis defined for negative 2. Negative 2 is less than orequal to x, which is less than or equal to 5. If you give me an x anywherein between negative 2 and 5, I can look at this graph to seewhere the function is defined. f of negative 2 is negative 4. f of negative 1 is negative 3. So on and so forth,and I can even pick the values inbetween these integers. So negative 2 is less than orequal to x, which is less than or equal to 5.
