How whould investingin human capital compact the gdp of a country

They tend to increase the GDP of the country.

Explanation:

GDP is calculated by adding a country's Consumption , investment, Government spending, and net Export.

If a government spent money to create programs that increase human's capital, that spending will be considered as 'Government Spending' within the calculation. As a result, this will increase the amount of GDP that the country produce in that year. On top of that, investing in human capital tend to also accelerate the growth rate of GDP in the future. Increasing quality of human capitals tend to attract investments from foreign countries.

i dont know but thats a great qusestion