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.
Both top out at about 5 feet. Similarly, the Lagerstroemia indica Razzle Dazzle series, which reaches heights of 4 feet, includes varieties such as Cherry Dazzle and Ruby Dazzle.. Dwarf crape myrtles grow well in U.S. Department of Agriculture plant hardiness zones 6 through 9.