## STACK Documentation

Documentation home | Category index | Site map# EquivFirst: Answer test results

This page exposes the results of running answer tests on STACK test cases. This page is automatically generated from the STACK unit tests and is designed to show question authors what answer tests actually do. This includes cases where answer tests currentl fail, which gives a negative expected mark. Comments and further test cases are very welcome.

## EquivFirst

Test | ? | Student response | Teacher answer | Opt | Mark | Answer note | |
---|---|---|---|---|---|---|---|

EquivFirst | x |
[x^2=4,x=2 or x=-2] |
-1 | ATEquivFirst_SA_not_list. | |||

The first argument to the Equiv answer test should be a list, but the test failed. Please contact your teacher. | |||||||

EquivFirst | [x^2=4,x=2 or x=-2] |
x |
-1 | ATEquivFirst_SB_not_list. | |||

The second argument to the Equiv answer test should be a list, but the test failed. Please contact your teacher. | |||||||

EquivFirst | [1/0] |
[x^2=4,x=2 or x=-2] |
-1 | ATEquivFirst_STACKERROR_SAns. | |||

EquivFirst | [x^2=4,x=2 or x=-2] |
[1/0] |
-1 | ATEquivFirst_STACKERROR_TAns. | |||

EquivFirst | [x^2=4,x=2 or x=-2] |
[x^2=4,x=2 or x=-2] |
1 | (EMPTYCHAR, EQUIVCHAR) | |||

\\[\\begin{array}{lll} &x^2=4& \\cr \\color{green}{\\Leftrightarrow}&x=2\\,{\\text{ or }}\\, x=-2& \\cr \\end{array}\\] | |||||||

EquivFirst | [x^2=9,x=3 or x=-3] |
[x^2=4,x=2 or x=-2] |
0 | ATEquivFirst_SA_wrong_start | |||

The first line in your argument must be "\\(x^2=4\\)". | |||||||

EquivFirst | [x^2=4,x=2] |
[x^2=4,x=2 or x=-2] |
0 | (EMPTYCHAR,IMPLIEDCHAR) | |||

\\[\\begin{array}{lll} &x^2=4& \\cr \\color{red}{\\Leftarrow}&x=2& \\cr \\end{array}\\] | |||||||

EquivFirst | [x^2=4,x^2-4=0,(x-2)*(x+2)=0,x =2 or x=-2] |
[x^2=4,x=2 or x=-2] |
1 | (EMPTYCHAR, EQUIVCHAR, EQUIVCHAR, EQUIVCHAR) | |||

\\[\\begin{array}{lll} &x^2=4& \\cr \\color{green}{\\Leftrightarrow}&x^2-4=0& \\cr \\color{green}{\\Leftrightarrow}&\\left(x-2\\right)\\cdot \\left(x+2\\right)=0& \\cr \\color{green}{\\Leftrightarrow}&x=2\\,{\\text{ or }}\\, x=-2& \\cr \\end{array}\\] | |||||||

EquivFirst | [x^2=4,x= #pm#2, x=2 or x=-2] |
[x^2=4,x=2 or x=-2] |
1 | (EMPTYCHAR, EQUIVCHAR, EQUIVCHAR) | |||

\\[\\begin{array}{lll} &x^2=4& \\cr \\color{green}{\\Leftrightarrow}&x= \\pm 2& \\cr \\color{green}{\\Leftrightarrow}&x=2\\,{\\text{ or }}\\, x=-2& \\cr \\end{array}\\] | |||||||

EquivFirst | [x^2-6*x+9=0,x=3] |
[x^2-6*x+9=0,x=3] |
1 | (EMPTYCHAR,SAMEROOTS) | |||

\\[\\begin{array}{lll} &x^2-6\\cdot x+9=0& \\cr \\color{green}{\\text{(Same roots)}}&x=3& \\cr \\end{array}\\] | |||||||

EquivFirst | [x^2=4,x=2] |
[x^2=4,x=2] |
[assumepos] |
1 | (ASSUMEPOSVARS, EQUIVCHAR) | ||

\\[\\begin{array}{lll}\\color{blue}{\\text{Assume +ve vars}}&x^2=4& \\cr \\color{green}{\\Leftrightarrow}&x=2& \\cr \\end{array}\\] | |||||||

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