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.
Crape myrtles (Lagerstroemia indica) are deciduous trees that grow between 18 inches and 40 feet tall, depending on the cultivar. They have simple opposite leaves that turn to red or yellow in the fall. Their large clusters of flowers come in a variety of colors such as red, pink and purple.