Prove that : - cos3a-cosa/sin3a-sina+cos2a-cos4a/s in4a-sin2a=sina/cos2acos3a

Kayla wants to find the width, ab, of a river. she walks along the edge of the river 65 ft and marks point c. then she walks 25 ft further and marks point d. she turns 90° and walks until her location, point a, and point c are collinear. she marks point e at this location, as shown. (a) can kayla conclude that δ and δ are similar? why or why not? (b) suppose de = 15 ft. what can kayla conclude about the width of the river?

According to the data set, where should the upper quartile line of the box plot be placed?

Write an inequality for this sentence the quotient of a number and -5 increased by 4 is at most 8