represents the antiderivative \({\mathop{\rm F}\nolimits} \) of \({\mathop{\rm f}\nolimits} \) with \({\mathop{\rm F}\nolimits} \left( 0 \right) = 0\), and \(T\left( {\mathop{\rm g}\nolimits} \right)\) represents the antiderivative \({\mathop{\rm G}\nolimits} \) of \({\mathop{\rm g}\nolimits} \) with \({\mathop{\rm G}\nolimits} \left( 0 \right) = 0\).
According to the rules of antidifferentiation, \({\mathop{\rm F}\nolimits} + G\) is the antiderivative of \({\mathop{\rm f}\nolimits} + {\mathop{\rm g}\nolimits} \). Then,
\(\begin{array}{c}\left( {{\mathop{\rm F}\nolimits} + G} \right)\left( 0 \right) = \left( {\mathop{\rm F}\nolimits} \right)\left( 0 \right) + \left( G \right)\left( 0 \right)\\ = 0 + 0\\ = 0\end{array}\)
Therefore, \(T\left( {{\mathop{\rm f}\nolimits} + g} \right) = T\left( {\mathop{\rm f}\nolimits} \right) + T\left( g \right)\).
Similarly, \(c{\mathop{\rm F}\nolimits} \) is an antiderivative of \({\mathop{\rm cf}\nolimits} \).
\(\begin{array}{c}\left( {c{\mathop{\rm F}\nolimits} } \right)\left( 0 \right) = c{\mathop{\rm F}\nolimits} \left( 0 \right)\\ = c0\\ = 0\end{array}\)
Therefore, \(T\left( {c{\mathop{\rm f}\nolimits} } \right) = cT\left( {\mathop{\rm f}\nolimits} \right)\), and \(T\) is a linear transformation.
Thus, it is proved that \(T\) is a linear transformation.