On a coordinate plane, a vector has an origin (3, -6) and terminal point (-4,1). Which description of the vector shown is correct?

The magnitude is 7 StartRoot 2 EndRoot, and the direction angle is approximately 315°.
The magnitude is 7 StartRoot 2 EndRoot, and the direction angle is approximately 135°.
The magnitude is StartRoot 6 EndRoot, and the direction angle is approximately 315°.
The magnitude is StartRoot 6 EndRoot, and the direction angle is approximately 135°.

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)