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.
Prune crepe myrtles a second time, after the spring flowers fade. This encourages more flowering and heavy pruning is usually not necessary. To prune a crepe myrtle, remove branches that rub against or cross each other. Take out dead or diseased looking limbs.