An inflection point is a point on a curve at which the sign of the curvature (i.e., the concavity) changes. Inflection points may be stationary points, but are not local maxima or local minima. For example, for the curve plotted above, the point is an inflection point. The first derivative test can sometimes distinguish inflection points from extrema for differentiable functions . The second derivative test is also useful. A necessary condition for to be an inflection point is . A sufficient condition requires and to have opposite signs in the neighborhood of (Bronshtein and Semendyayev 2004, p. 231).
Rice vermicelli are thin rice-flour noodles common in Chinese, Thai, Vietnamese, and other Southeast Asian cuisines, where they are often used in stir-fries, soups, spring rolls, and salads. Don't confuse rice vermicelli with cellophane noodles, another thin Asian noodle that's made with mung bean starch.
Vermicelli is a type of fine pasta that is similar to spaghetti. The pasta features long rounded pasta strands that tend to be slightly thinner than spaghetti and somewhat thicker than angel hair pasta. In Italian, vermicelli literally means little worms and reflects the pastas distinctive worm-like shape.