\int\limits_0^t {x(\tau )d} \tau \Leftrightarrow \frac{1}{s}X(s)
% MathType!MTEF!2!1!+- % feaafaart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY-Hhbbf9v8qqaqFr0xc9pk0xbb % a9q8WqFfeaY-biLkVcLq-JHqpepeea0-as0Fb9pgeaYRXxe9vr0-vr % 0-vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaamaapehabaGaam % iEaiaacIcacqaHepaDcaGGPaGaamizaaWcbaGaaGimaaqaaiaadsha % a0Gaey4kIipakiabes8a0jabgsDiBpaalaaabaGaaGymaaqaaiaado % haaaGaamiwaiaacIcacaWGZbGaaiykaaaa!481C!
Pasting the above "text" into MathType 5.0 will enter the above equation and make it possible to edit, save, and use in applications such as MS Word.