What is direct proportion ?

Direct proportion means that as one variable goes up the other goes up by the same factor.

What is inverse proportion ?

Inverse proportion means as one variable goes up the other goes down by the same factor.

True or False? The graph of two directly proportional variables is a straight line.

True. The graph of two directly proportional variables is a straight line.

IGCSEMaths A: HigherEdexcelFlashcards

Direct & Inverse Proportion (Edexcel IGCSE Maths A)

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What is direct proportion?

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What is direct proportion?
Direct proportion means that as one variable goes up the other goes up by the same factor.
True or False?
If $x$ and $y$ are directly proportional, then $x : y$ will always be the same.
True.
If $x$ and $y$ are directly proportional, then $x : y$ will always be the same.
What is $k$ used to represent when working with direct and inverse proportions?
When working with direct and inverse proportions, $k$ is used to represent the constant of proportionality that connects $x$ and $y$ .
$y = k x$ when $x$ and $y$ are directly proportional.
$y = \frac{k}{x}$ when $x$ and $y$ are inversely proportional.
What does it mean for $y$ to be directly proportional to the square of $x$ ?
If $y$ is directly proportional to the square of $x$ , it means that $y = k x^{2}$ .
What is inverse proportion?
Inverse proportion means as one variable goes up the other goes down by the same factor.
True or False?
If $x$ is inversely proportional to $y$ , then $x : y$ will always be the same.
False.
If $x$ is inversely proportional to $y$ , then $x : \frac{1}{y}$ will always be the same.
How would you describe the relationship between $A$ and $B$ if $A = \frac{k}{B}$ ?
If $A = \frac{k}{B}$ , it means that $A$ is inversely proportional to $B$ .
What is the equation for $A$ in terms of $B$ if $A$ is inversely proportional to the square of $B$ ?
If $A$ is inversely proportional to the square of $B$ , then $A = \frac{k}{B^{2}}$ .
True or False?
The graph of two directly proportional variables is a straight line.
True.
The graph of two directly proportional variables is a straight line.
True or false?
When solving a direct/inverse proportion problem, one of the first things you should do is find the value of the constant of proportionality $k$ .
True.
When solving a direct/inverse proportion problem, one of the first things you should do is find the value of the constant of proportionality $k$ .
What is the formula for $y$ in terms of $x$ if $y$ is inversely proportional to the cube root of $x$ ?
If $y$ is inversely proportional to the cube root of $x$ , then $y = \frac{k}{\sqrt[3]{x}}$ .
Using laws of indices that can also be written as $y = \frac{k}{x^{\frac{1}{3}}}$ or $y = k x^{- \frac{1}{3}}$ .

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