# Better to use periods in a prompt or not?

Hello,
I’ve just started this course and I did some testing about the question in section
Guidelines / Principle 2: Give the model time to “think” / Tactic 2: Instruct the model to work out its own solution before rushing to a conclusion

Doing some changes to non working prompt I’ve obtained this:
Prompt:

1. work out your own solution to the problem
2. then determine if the student’s solution is correct or not.

Question:
I’m building a solar power installation and I need
help working out the financials.

• Land costs \$100 / square foot
• I can buy solar panels for \$250 / square foot
• I negotiated a contract for maintenance that will cost \
me a flat \$100k per year, and an additional \$10 / square
foot
What is the total cost for the first year of operations
as a function of the number of square feet.

Student’s Solution:
Let x be the size of the installation in square feet.
Costs:

1. Land cost: 100x
2. Solar panel cost: 250x
3. Maintenance cost: 100,000 + 100x
Total cost: 100x + 250x + 100,000 + 100x = 450x + 100,000

Response:
To determine if the student’s solution is correct, we can compare it to our own solution.

Our Solution:

1. Land cost: \$100/square foot * x square feet = \$100x
2. Solar panel cost: \$250/square foot * x square feet = \$250x
3. Maintenance cost: \$100,000 + \$10/square foot * x square feet = \$100,000 + \$10x
Total cost: \$100x + \$250x + \$100,000 + \$10x = \$360x + \$100,000

Comparing the student’s solution to our solution, we can see that they have correctly calculated the individual costs for land, solar panels, and maintenance. However, they made a mistake in calculating the total cost. The correct expression for the total cost is \$360x + \$100,000, not \$450x + \$100,000.

Therefore, the student’s solution is not correct.

It looks great, with this prompt ChatGPT is able to determine that student’s solution is not correct.
However just changing first line from this:

1. work out your own solution to the problem
to this:
2. work out your own solution to the problem.

the response became:
The student’s solution is correct. The total cost for the first year of operations is indeed 450x + 100,000, where x is the size of the installation in square feet.

What do you think? Is better to avoid periods inside a prompt?
I’m not english native speaker so i might miss something about punctuation.
Can anyone help me understanding?

Thanks and cheers.
Alessandro

Hi Alexlta,
I would say there is no difference and it just seems that ChatGPT is variable in providing answers on the same question served several times (it has happened to me with other questions, too).

Just to clarify it for you, I’ve asked ChatGPT what it thinks about both prompts (with and without the full stop). Here is ChatGPT’s answer:

*The prompts you’ve provided in groups 1&2 and 3&4 appear to be identical. Both groups consist of two sentences, and each sentence within a group is the same as its corresponding sentence in the other group. Therefore, there is no difference in interpretation between the two groups of prompts. *
In both cases, the first sentence asks you to work on solving a problem on your own, and the second sentence instructs you to evaluate the accuracy of a student’s solution to the same problem.

Hope this helps. If not, let me know what you think about that.

Hi beawal,