A variable, Y, is inversely proportional to another variable, X if XY = k for some positive constant k. An equivalent formulation is Y = k/X. What this means is that if you double X, then Y is halved. If you treble X then Y is reduced to a third etc.
The two lines are y = 2x + k and y = x² - 2x - 7 Which means they meet at: 2x + k = x² - 2x - 7 → x² - 4x - (k+7) = 0 This can be solved using the formula for quadratics: x = (- -4 ± √((-4)² - 4×1×-(k+7)))/2 = 2 ± √(4 + k + 7) = 2 ± √(k + 11) This has one solution when the determinant (the part in the square root) is 0, ie k + 11 = 0 → k = -11 If the determinant is positive, there are two solutions, ie k + 11 > 0 → k > -11 Thus the there are two distinctive points if k > -11, and only 1 point if k = -11.
Suppose the amount invested (or borrowed) is K, Suppose the rate of interest is R% annually, Suppose the amount accrues interest for Y years. Then the interest I is 100*K[(1 + R/100)^Y - 1]
There are different types of variation in math - direct variation, inverse variation, and joint variation for a start. Direct variation is just simply that x and y vary directly. What this means is that they do the same thing - as x increases so does y, or as x decreases so does the value of y. In general the formula for direct variation is y=kx where k is the constant of variation. (For example we could have a direct variation equation such as y=2x. The constant of variation is 2, which just means that as x increases, y doubles that amount and thus also increases) Inverse variation is when x and y do the opposite of each other. So as x increases, y decreases or as x decreases the value of y increases. One fun example of where this happens in real life is with Ramen Noodles - the less money people make the more Ramen Noodles they buy. We would say that people's income and the amount of Ramen Noodles they buy vary inversely. In general the formula for inverse variation is y = k/x where again k is the constant of variation. Joint variation is when you have three variables that are related. The general formula for joint variation is y=kxz where z is just a third variable and k is still the constant of variation.
Various options: y is directly proportional to k, with x as the constant of proportionality; y is directly proportional to x, with k as the constant of proportionality; x is inversely proportional to k, with y as the constant of proportionality; x is directly proportional to y, with 1/k as the constant of proportionality; k is directly proportional to y, with 1/x as the constant of proportionality; and k is inversely proportional to x, with y as the constant of proportionality.
y means and
Using the distance formula it is the square root of: (h-x)^2 +(k-y)^2
Formula of a circle in a Cartesian plane: (x-h)^2+ (y-k)^2 = r^2 where the center is at (h,k) and the radius is r.
Equations: y = 3x +1 and x^2 +y^2 = k If: y = 3x +1 then y^2 = 9x^2 +6x +1 If: x^2 +y^2 = k then y^2 = k -x^2 Transposing terms: 10x^2 +6x +(1 -k) = 0 Using the discriminant formula: k = 1/10 Using the quadratic equation formula: x = -3/10 By substitution: y = 1/10
It is a straight line through the origin and, if k > 0 reflects a direct relationship between x and y. This means that each unit increase in x is associated with y increasing by k. If k < 0 it reflects a direct but negative relationship and this means that each unit increase in x is associated with y decreasing by k. If k = 0 then the result is the x-axis. This means that changes in x are not associated with changes in y. None of the above imply causation.
If: y = x^2 -2x -7 and y = 2x +k Then: x^2 -2x -7 = 2x +K Transposing terms: x^2 -4x +(-7 -k) = 0 Using the discriminant formula: 4^2 -4*1*(-7 -k) = 0 => k = -11 Using the quadratic equation formula: x^2 -4x +4 = 0 => x = 2 By substitution: y = -7 Therefore the values of the variables are: k = -11, x = 2 and y = -7
Formula of a circle in a Cartesian plane: (x-h)^2+ (y-k)^2 = r^2 where the center is at (h,k) and the radius is r.
A variable, Y, is inversely proportional to another variable, X if XY = k for some positive constant k. An equivalent formulation is Y = k/X. What this means is that if you double X, then Y is halved. If you treble X then Y is reduced to a third etc.
It means: And what are you doing right now?
"Y tú, ¿qué estás haciendo?" means, "And you? What are you doing?"
The formula for a potassium ion is K+. This means that the ion has lost one electron, giving it a +1 charge.
The constant of variation in a direct variation is the constant (unchanged) ratio of two variable quantities. The formula for direct variation is. y=kx (or y=kx ) where k is the constant of variation .