1-cosx/1+cosx=secx-1/secx+1 Verify the identity. I tried all identities that I could, but could not find how it worked. Can you show me how to verify with all steps?

I usually do not ask on but I've tried everything else and still got nothing.
Currently in Algebra 2 and in the 9th grade.

The mean of a set of data is -3.82 and its standard deviation is 2.31. find the z score for a value of 3.99.

Someone answer this asap rn for ! a discount store’s prices are 25% lower than department store prices. the function c(x) = 0.75x can be used to determine the cost c, in dollars, of an item, where x is the department store price, in dollars. if the item has not sold in one month, the discount store takes an additional 20% off the discounted price and an additional $5 off the total purchase. the function d(y) = 0.80y - 5 can be used to find d, the cost, in dollars, of an item that has not been sold for a month, where y is the discount store price, in dollars. create a function d(c(x)) that represents the final price of an item when a costumer buys an item that has been in the discount store for a month. d(c(x)) =

Due to a packaging error, 4 cans labeled diet soda were accidentally filled with regular soda and placed in a 12 pack carton of diet soda. two cans were randomly selected from this 12 pack. what is the probability that both cans were regular soda?