Simplify the expression:
cos^2(pi-x)/sqrt1-sin^2(x)
a. tan(x)
b. cos(x) tan(x)
c. cos(x) cot(x)
d. sin(x) tan(x)

−[cos2(x)√−(sin(x)+1)(sin(x)−1)] / [(sin(x)+1)(sin(x)−1)] I belive is the answer 

Formula
cos(pi - x) = -cos(x)
cos^2(x) + sin^2(x) = 1

i think you mean this
cos^2(pi-x) / sqrt[ 1-sin^2(x) ]
= cos^2(x) / sqrt[ cos^2(x) ]
= cos^2(x) / | cos(x) |
= | cos(x) |

if so, none is correct

The major difference is that a histogram is only used to plot the frequency of score occurrences in a continuous data set that has been divided into classes, called bins.  bar charts, on the other hand, can be used for a great deal of other types ofvariables  including  ordinal  andnominal  data sets.