\frac{d}{{dx}}\int\limits_a^x {f\left( s \right)} ds = f\left( x \right)
% MathType!MTEF!2!1!+- % feaafaart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqr1ngB % PrgifHhDYfgasaacH8YjY-vipgYlh9vqqj-hEeeu0xXdbba9frFj0- % OqFfea0dXdd9vqai-hGuQ8kuc9pgc9q8qqaq-dir-f0-yqaiVgFr0x % fr-xfr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaae % aacaWGKbaabaGaamizaiaadIhaaaWaa8qCaeaacaWGMbWaaeWaaeaa % caWGZbaacaGLOaGaayzkaaaaleaacaWGHbaabaGaamiEaaqdcqGHRi % I8aOGaamizaiaadohacqGH9aqpcaWGMbWaaeWaaeaacaWG4baacaGL % OaGaayzkaaaaaa!488E!
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.