The domain of a vector function r(t) consists of all values of t for which the expression for r(t) is defined. therefore, to find the domain, find the intervals where each component is defined, then find their intersection. the first component of r(t) = 25 − t2 , e−6t, ln(t + 4) , namely 25 − t2 , is defined as long as 25 − t2 ≥ 0. this means t must be in the interval