Defining the cotangent function. The cotangent function is an old mathematical function. It was mentioned in 1620 by E. Gunter who invented the notation of cotangens. Later on J. Keill (1726) and L. Euler (1748) used this function and its notation in their investigations.
Crepe Myrtles are among the toughest, most adaptable, and showiest plants that can be grown in the Texas landscape. Along with their bright colorful bloom display during the summer months the leaves of the Crepe Myrtle also turn orange, red and yellow in the fall.
Crepe or Crape Myrtles. Another plant with a similar name, the crepe myrtle, is actually a tree that produces flowers throughout the summer. This plant variety is non-toxic to dogs.reeping myrtle, also known as running myrtle, Vinca minor and lesser periwinkle, is a fast-spreading evergreen ground cover with shiny green leaves and blue flowers.