Answer:
Rui will reach his lowest altitude after 20seconds of diving
Step-by-step explanation:
Given the function that models the altitude of Rui at any time x expressed as:
d(x) = 1/2 x² - 10x
The height of rui at his lowest altitude will be zero. Substitute d(x) = 0 into the expression and get x
d(x) = 1/2 x² - 10x
0 = 1/2 x² - 10x
-1/2x² = 10x
1/2 x = 10
Multiply both sides by 2
x/2 × 2 = 10×2
x×1 =20
x = 20
Hence Rui will reach his lowest altitude after 20seconds of diving