Issue with Pattern

Questions
1

In the ip6a box - it is grading as correct when the standard form is written as an expression (no y=) but not when written as an equation (with the y=).

How do I change the pattern to require the equation instead of the expression?

Thanks so much for your help!

2

You could use parseEquation( ).differenceFunction( ) to graph instead of simpleFunction( ). You’d use 0=f(x,y) to graph it.

This would check if it’s an equation at all:

when isUndefined(parseEquation(this.latex)) "Not an equation"

As to the pattern matching, you can use parseEquation( ).lhs or .rhs to pattern match one side of the equation.

There may also be an issue with the answer being a combination of sum and difference. I haven’t worked enough with it to give you a definite though.

3

Thanks for your help! I haven’t used parseEquation before, could you tell me how to add that to the code I have?

submitLabel: “Check my Standard Form equation”

p=patterns

standard=p.anyOf(
p.difference(p.expression,p.expression,p.expression),
p.difference(p.expression,p.expression),
p.sum(p.expression,p.expression,p.expression),
p.sum(p.expression,p.expression)
)

errorMessage: when not(standard.matches(this.latex)) “Did you write your equation in standard form?” otherwise “”

fn1 = simpleFunction(this.latex)

disableEvaluation: true

checkfunction = fn1.evaluateAt(-2) = -10 and fn1.evaluateAt(2) = -6 and fn1.evaluateAt(1) = -10

correct = checkfunction and standard.matches(this.latex)
correct: checkfunction and standard.matches(this.latex)

4

This checks if y= is entered on the left hand side, although Daniel’s suggestion would work too. This wouldn’t work if a student enters f(x) though, which is why it might be better to check if the equation is defined. To alleviate that, you could just put in the errorMessage to enter a standard form equation starting with y=.

submitLabel: "Check my Standard Form equation"

left = parseEquation(this.latex).lhs
right = parseEquation(this.latex).rhs

p=patterns

matchLeft = p.literal("y").matches(left)

standard=p.anyOf(
p.difference(p.expression,p.expression,p.expression),
p.difference(p.expression,p.expression),
p.sum(p.expression,p.expression,p.expression),
p.sum(p.expression,p.expression)
)

matchRight = standard.matches(right)

errorMessage: when not(matchRight) or not(matchLeft) "Did you write your equation in standard form?" otherwise ""

fn1 = simpleFunction(this.latex)

disableEvaluation: true

correct = fn1.evaluateAt(-2) = -10 and fn1.evaluateAt(2) = -6 and fn1.evaluateAt(1) = -10

correct: correct
5 
errorMessage: when isUndefined(parseEquation(this.latex)) or
 not(standard.matches(parseEquation(this.latex).lhs)) "Did you write your equation in standard form?"
 otherwise ""

Then change this:

fn1= parseEquation(this.latex).differenceFunction("x","y")

In the graph component:

function(`f`): ip6a.script.fn1

In the graph

0=f(x,y)
6

I sincerely appreciate all of the help. I tried both of your ideas (on pages 2 and 3, attached). On one I am getting an error in the computation layer, and in the other it still isn’t “grading” correctly when typed in and is still getting a red x instead of a green check.

I was wondering if you could help me finish this up?

Thank you SO much!

7

The error in ip6a is that since the difference function (which is lhs - rhs) is in terms of x and y you need to put both x and y in evaluateAt. Solutions to the differenceFunction should always equal 0:

checkfunction = fn1.evaluateAt(-2,-10) = 0 and fn1.evaluateAt(2,-6) = 0 and fn1.evaluateAt(1,-10) = 0