The fourth through the seventh terms of an arithmetic sequence are given by a4 = 17, a5 = 21, a6 = 25, and a7 = 29. Which formula can be used to find an?

A. an= 17+4(n-1)
B. an= 9+4(n+1)
C. an= 5+4(n-1)
D. an= 5+4(n+1)
E. an= 4+5(n-1)

Which one is the correct answer, and why?

I've been working on this for a few days and i just don't understand, it's due in a few hours. you.the direction of a vector is defined as the angle of the vector in relation to a horizontal line. as a standard, this angle is measured counterclockwise from the positive x-axis. the direction or angle of v in the diagram is α.part a: how can you use trigonometric ratios to calculate the direction α of a general vector v = < x, y> similar to the diagram? part bsuppose that vector v lies in quadrant ii, quadrant iii, or quadrant iv. how can you use trigonometric ratios to calculate the direction (i.e., angle) of the vector in each of these quadrants with respect to the positive x-axis? the angle between the vector and the positive x-axis will be greater than 90 degrees in each case.part cnow try a numerical problem. what is the direction of the vector w = < -1, 6 > ?

Marking brainliest for original answer.. are these two triangles similar? how can you tell?