what conjecture can you make about the sum of the first 40 positive even numbers? 2=2=1x2 2+4=6=12=3x4 2+4+6+8=20=4x5 2+4+6+8+10=30=5x6

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)