Mathematical statements

Mathematical statements

Discover the difference between:

expressions, equations, identities and formulae.

An expression

• Is a collection of alphanumerics with no =

• Examples x²+3, 4y + 2z

An equation

• This MUST have the = sign. You will be evaluating one variable

• Examples: 3x = 24, x + 4 = 2x -6

• You may think the y= x² + 3x - 6 involves finding 2 variable, but remember we are substituting different values of x to find each y

An identity

• This is an equation including variables which is true no matter what value the variable has.

• Examples may be: 

   $x\times x\equiv x^2$  

• You will notice that the "identity" symbol has an extra horizontal line!

• Another example $2x\ \equiv x+x$  

A formula

• This includes many variables. It is a way of finding one variable when we know all the others.

• Remember these are not ALWAYS true for every possible value of the variable.

• Examples

   $v=u+at$  or more famously  $e=mc^2$  

Multiple Choice

Which classification would you put the following?

 $a\ =\ r\Theta$  ?

• Identity

• Formula

• Equation

• Expression

Multiple Choice

Classify the following:

 $7x^2-4x+3$  

• Equation

• Expression

• Identity

• Formula

Multiple Choice

 $v=u+\frac{1}{2}at^2$  is which?

• equation

• expression

• identity

• formula

Multiple Select

What symbol would you use to link the following two expressions?

 $x^4\ \ \ \ \ \ \ \ and\ \ \ \ \ \ \ x^2\times x^2$  

•  $>$  

•  $=$  

•  $\cong$  

•  $\equiv$  

Poll

How well do you think you have learned about equations, formulae, identities and equations using this approach?

• I didn't really get on well with it.

• It was OK, but I do not think it is the best way.

• I quite enjoyed it, but need to get more used to it.

• I enjoy this approach and would like to try it again.