Hello All,
I have an answer formula "(((([y]/100)+1)**18-1)*[x] *1000)/([y]/100)" in a calculated question of WebCT CE6. I need to convert this question on the Moodle version. Please note that x and y are variables on this question.
Please help me.
In reply to Ranjith Valliyedath
Re: Using exponent function in the calculated Questions
by Pierre Pichet -
Hi Ranjith,
First look at the help button on the upper part of the editing form of the calculated question.
There is also a reference to moodle docs at the editing form page.
So x and y will become {x} and {y} and you will be able to define there numerical values.
The other problem is that Moodle use mathematical php functions so that ** is converted to a power(...,...) function.
Being a teacher I let you find how to use the power function in your equation
as your homework.
Pierre
First look at the help button on the upper part of the editing form of the calculated question.
There is also a reference to moodle docs at the editing form page.
So x and y will become {x} and {y} and you will be able to define there numerical values.
The other problem is that Moodle use mathematical php functions so that ** is converted to a power(...,...) function.
Being a teacher I let you find how to use the power function in your equation
as your homework.Pierre
In reply to Pierre Pichet
Re: Using exponent function in the calculated Questions
by Ranjith Valliyedath -
Hi Pierre,
Many thanks for your reply. This will help. But i am still struggling to get the same answers which are appearing on the WebCT. Could you please provide me a answer formula for this one?
Regards,
Ranjith.
In reply to Ranjith Valliyedath
Re: Using exponent function in the calculated Questions
by Pierre Pichet -
On the docs that you can access from the bottom of the calculated question it is specified that pow (numberToRaise, NumberRaisedTo)
i.e pow(2,4) = 16 i.e 24
So (((([y]/100)+1)**18-1)*[x] *1000)/([y]/100)
becomes
(({y}/100)+1)**18
becomes
pow( (({y}/100)+1) , 18 )
then
( pow( (({y}/100)+1) , 18 )-1)*{x}*1000
then
( ( pow( (({y}/100)+1) , 18 )-1)*{x}*1000 ) / ({y}/100)
you remove the space and obtain a valid formula
i.e pow(2,4) = 16 i.e 24
So (((([y]/100)+1)**18-1)*[x] *1000)/([y]/100)
becomes
(({y}/100)+1)**18
becomes
pow( (({y}/100)+1) , 18 )
then
( pow( (({y}/100)+1) , 18 )-1)*{x}*1000
then
( ( pow( (({y}/100)+1) , 18 )-1)*{x}*1000 ) / ({y}/100)
you remove the space and obtain a valid formula
((pow((({y}/100)+1),18)-1)*{x}*1000)/({y}/100)
that gives 64236.94 when {y} = 2 and {x} = 3
My conclusion is that analytical chemistry equations are easier...
Pierre
that gives 64236.94 when {y} = 2 and {x} = 3
My conclusion is that analytical chemistry equations are easier...
Pierre
In reply to Pierre Pichet
Re: Using exponent function in the calculated Questions
by Tiffany Hoefer -
I am having a similar problem. I tried to apply Pierre's example to my particular problem but I obviously still can't apply the logic. Our instructor needs to measure exponents and decay and has the following question:
The Mendes family bought a new house {years} years ago for ${purchase},000. The house is now worth ${current},000. Assuming a steady rate of growth, what was the yearly rate of appreciation? Round your answer to the nearest tenth of a percent (1.2% etc)
They want the student to solve it by using the following formula: 1 minus {current} divided by {purchase} to the power of 1/{years}.
When I try to write the answer formula as: 1-{current}/{purchase}pow(1/{years}), I receive the error "the function 1pow is not supported". I have tried many other incarnations but this was the most promising error message of all. I usually receive a syntax error which leads me to believe that for those I just had it totally wrong.
Any ideas on how to render this formula? Any kind words are appreciated.
In reply to Tiffany Hoefer
Re: Using exponent function in the calculated Questions
by Pierre Pichet -
The pow function is somehow tricky to use.
Calculated question docs :
pow (numberToRaise, NumberRaisedTo)
So your formula should be something as
1-pow({current}/{purchase},1/{years})
and for a house worthing $100,000 and purchased for $50,000 5 years ago this should give
1-pow(100000/50000,1/5) = -0.15
This is the same result as obtained in excel with =1-((100000/50000)^(1/5))
If I understand correctly your function...
Looking on other sites as
http://www.forsalebyowner.com/sell-my-house/deciding/how-to-calculate-average-rate-of-appreciation
your function could be (pow({current}/{purchase},1/{years})-1) * 100
In reply to Pierre Pichet
Re: Using exponent function in the calculated Questions
by Tiffany Hoefer -
Pierre,
Thank you so much for your help! These are quite tricky, and I really appreciate you getting me past the dreaded error screen.
In reply to Ranjith Valliyedath
Re: Using exponent function in the calculated Questions
by Peter Halverson -
Just a comment...
You should take a look at the "Formulas Question Type" for Moodle.
https://moodle.org/plugins/view/qtype_formulas
I like it better than the "Calculated Question Type."
It does require an administrator to install it and it does take some effort to learn how to use it, but I think its easier than Calculated.
---Peter H.
In reply to Peter Halverson
Re: Using exponent function in the calculated Questions
by Tiffany Hoefer -
Peter,
Thank you for the suggestion. I'll definitely give it a look and see if our administrator will buy in. Thanks!!