Question Number 7499 by Tawakalitu. last updated on 31/Aug/16
$${Let}\:{E}\:{be}\:{a}\:{banach}\:{space}\:,\:{Y}\:{is}\:{normed}\:{space}\:{and}\: \\ $$$${suppose}\:{that}\:\left\{{Ta}\::\:{a}\in{A}\right\}\:\subseteq\:\:{B}\:\left({E},\:{Y}\right)\:{If}\:\left\{{Tax}\::\:{a}\in{A}\right\} \\ $$$$\subseteq\:{Y}\:{is}\:{bounded}\:,\:{for}\:{all}\:{x}\in{E},\:{then}\:\left\{\parallel{Ta}\parallel\::\:{a}\in{A}\right\}\:{is}\: \\ $$$${bounded}. \\ $$