I'm single any girl of 15 yrs

Which sum or difference identity would you use to verify that cos (180° - ∅) = -cos ∅? a. sin (α -β) = sin α cos β – cos α sin β b. cos (α -β) = cos α cos β – sin α sin β c. cos (α -β) = cos α cos β + sin α sin β d. sin (α + β) = sin α cos β + cos α sin β

Abacteria population is tripling every hour. by what factor does the population change in 1/2 hour? select all that apply

How can you find the mean absolute deviation (mad) for this set of data?