The price of a notebook has dropped to $3.15 today. Yesterday's price was $3.40. Find the percentage decrease. Round your answer to the nearest tenth of a percent

Will give brainliest sum of arithmetic series (sigma notation) find the numerical answer to the summation given below. (image shown below)

Mary beth used the mapping rule to find the coordinates of a point that had been rotated 90° counterclockwise around the origin. examine the steps to determine whether she made an error. m (3, –6) is rotated 90° counterclockwise. (x, y) → (–y, x) 1. switch the x- and y-coordinates: (6, –3) 2. multiply the new x-coordinate by –1: (6(–1), –3) 3. simplify: (–6, –3) .

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.