Home » Classroom » JAMB Mathematics 2009 Question

The distance travelled by a particle from a fix... - JAMB Mathematics 2009 Question

The distance travelled by a particle from a fixed point is given as s = (t3 - t2 - t + 5)cm. Find the minimum distance that the particle can cover from the fixed point.
A
2.3 cm
B
4.0 cm
C
5.2 cm
D
6.0 cm
correct option: c

S = t3 - t2 - t + 5
ds/dt = 3t2 - 2t - 1

As ds = 0

3t2 - 2t - 1 = 0

(3t+1)(t-1) = 0

∴ t = 1 or -1/3

At min pt t = -1/3

S = t3 - t2 - t + 5 put t = -1/3

= (-1/3)3 - (-1/3)2 - (-1/3) + 5

= -1/27 - 1/9 + 1/3 + 5

= 140 / 27

= 5.2

Please share this, thanks:

#JAMB #JAMB

Add your answer

Notice: Please post responsibly.

No responses