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Single-step methods (such as Euler's method) refer to only one previous point and its derivative to determine the current value. Methods such as Runge–Kutta take some intermediate steps (for example, a half-step) to obtain a higher order method, but then discard all previous information before taking a second step. Multistep methods attempt ...
Dynamical properties of reaction networks were studied in chemistry and physics after the invention of the law of mass action.The essential steps in this study were introduction of detailed balance for the complex chemical reactions by Rudolf Wegscheider (1901), [1] development of the quantitative theory of chemical chain reactions by Nikolay Semyonov (1934), [2] development of kinetics of ...
This term is often used in organic chemistry. For example, from the word ether , referring to an oxygen-containing compound having the general chemical structure R−O−R′ , where R and R′ are organic functional groups and O is an oxygen atom, comes the word thioether , which refers to an analogous compound with the general structure R−S ...
Finding the real roots of a polynomial with real coefficients is a problem that has received much attention since the beginning of 19th century, and is still an active domain of research. Most root-finding algorithms can find some real roots, but cannot certify having found all the roots.
This can be proved as follows. First, if r is a root of a polynomial with real coefficients, then its complex conjugate is also a root. So the non-real roots, if any, occur as pairs of complex conjugate roots. As a cubic polynomial has three roots (not necessarily distinct) by the fundamental theorem of algebra, at least one root must be real.
Newton's method is a powerful technique—in general the convergence is quadratic: as the method converges on the root, the difference between the root and the approximation is squared (the number of accurate digits roughly doubles) at each step. However, there are some difficulties with the method.
Real-root isolation is useful because usual root-finding algorithms for computing the real roots of a polynomial may produce some real roots, but, cannot generally certify having found all real roots. In particular, if such an algorithm does not find any root, one does not know whether it is because there is no real root.
The final step is reductive elimination of the two coupling fragments to regenerate the catalyst and give the organic product. Unsaturated substrates, such as C(sp)−X and C(sp 2 )−X bonds, couple more easily, in part because they add readily to the catalyst.