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.
A U.S. Department of Agriculture research scientist bred these beauties, and now they are grown by J. Berry Nursery in Texas. Five in series. The stunning black diamond crape myrtle has five different colors. We all know how different reds can be, and there is the Best Red, which is a very dark red. You might think it wouldn't show up with the dark burgundy leaves, but it is a beautiful mix of colors.
The Catawba Crepe Myrtle is a great deciduous shrub or small tree. One of the best purple crepe myrtles. The tree has attractive bark in the winter. The Country Red Crepe Myrtle is a deciduous ornamental tree with bright pinkie-red flowers in summer and orange-yellow color in fall.