# Question about writing out formulas (do I need to for full marks?)

Let’s say there’s a 4 minute question saying “show your calculations” on Cobb-Douglas, with:

Capital stock growth = 3%

Labour input growth = 2%

output elasticity of capital = 0.3

TFP growth = 2.5%.

My answer in my practice exams is:

Change in GDP = 2.5% + 3% * 0.3 + 2% * 0.7 = 4.8%

I give myself 4 marks out of 4 for that. Should I be writing out this instead?

Change in GDP = TFP growth + Capital stock growth * output elasticity of capital + labour input growth * (1-output elasticity of capital) [in words or symbols]

Change in GDP = 2.5% + 3% * 0.3 + 2% * 0.7 = 4.8%

Thoughts?

I use to write (whats d here is the greek delta when I write it in the exam): d%Y=d%TFP+(alpha)*d%C+(1-alpha)*d%L and then with numbers.

This way, if you calculate anything wrong, they still know what you meant. And the abbreviations are the same everywhere, graders will know it.

So write down the formula before putting in numbers, but don’t write it out in words, that’s not necessary.