In mathematics, specifically in calculus and complex analysis, the logarithmic derivative of a function f is defined by the formula where is the derivative of f. Intuitively, this is the infinitesimal relative change in f; that is, the infinitesimal absolute change in f, namely scaled by the current value of f. When f is a function f(x) of a real variable x, and takes real, strictly positive values, this is equal to the derivative of ln(f), or the natural logarithm of f.
Mathematical logic is the study of formal logic within mathematics. Major subareas include model theory, proof theory, set theory, and recursion theory (also known as computability theory). Research in mathematical logic commonly addresses the mathematical properties of formal systems of logic such as their expressive or deductive power. However, it can also include uses of logic to characterize correct mathematical reasoning or to establish foundations of mathematics.
The Book of Daniel is a 2nd-century BC biblical apocalypse with a 6th century BC setting. Ostensibly "an account of the activities and visions of Daniel, a noble Jew exiled at Babylon", it combines a prophecy of history with an eschatology (a portrayal of end times) both cosmic in scope and political in focus, and its message is that just as the God of Israel saves Daniel from his enemies, so he would save all Israel in their present oppression.
Daniel (Aramaic and דָּנִיֵּאל; Δανιήλ; دانيال) is the main character of the Book of Daniel. According to the Hebrew Bible, Daniel was a noble Jewish youth of Jerusalem taken into captivity by Nebuchadnezzar II of Babylon, serving the king and his successors with loyalty and ability until the time of the Persian conqueror Cyrus, all the while remaining true to the God of Israel.