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.
Tree to 25â30 ft. tall, 15â25 ft. wide. The showiest and most tender of the crepe myrtles, displaying huge clusters of white, pink, lavender, or purple flowers in June and July. Individual blossoms reach 3 in. across. Large leaves (8â12 in. long, 4 in. wide) turn red in fall.