What must be true of f(x) and g(x) if both are antiderivatives of f(x)?

The average human heart beats 1.15 \cdot 10^51.15⋅10 5 1, point, 15, dot, 10, start superscript, 5, end superscript times per day. there are 3.65 \cdot 10^23.65⋅10 2 3, point, 65, dot, 10, start superscript, 2, end superscript days in one year. how many times does the heart beat in one year? write your answer in scientific notation, and round to one decimal place.

What is the missing step in this proof ?

Extra points! find the missing dimension! need asap