Answer:
t ≤ 4.24
Step-by-step explanation:
P(t) ≥ 40000 implies
500t/(2t²+9) ≥ 40000
Multiplying through by t², we have
500t ≥ 40000(2t²+9)
500t/40000 ≥ 2t²+9
Collecting like terms
0.0125t ≥ 2t²+9
0 ≥ 2t²+ 9 - 0.0125t
2t²+ 9 - 0.0125t ≤ 0
2t²- 0.0125t + 9 ≤ 0
Using the quadratic formula,
[tex]t = \frac{-(-0.0125) +/-\sqrt{(-.0125)^{2} - 4 X 2 X 9} }{2 X 2} \\= \frac{0.0125 +/-\sqrt{(0.00015625 - 288} }{4}\\= \frac{0.0125 +/-\sqrt{-287.9998} }{4}\\= \frac{0.0125 +/-16.97i }{4}\\=0.00313 + 4.24i or 0.00313 - 4.24i[/tex]
The factors of the equation are (t - 0.00313 -4.24i) and (t - 0.00313 + 4.24i)
So, (t - 0.00313 -4.24i)(t - 0.00313 + 4.24i) ≤ 0
(t - 0.00313)² - 4.24² ≤ 0
(t - 0.00313)² ≤ 4.24²
taking square-root of both sides,
√(t - 0.00313)² ≤ √4.24²
t - 0.00313 ≤ 4.24
t ≤ 4.24 + 0.00313
t ≤ 4.24313 ≅ 4.24
t ≤ 4.24
