A bird flies from a tree. At time t seconds, the bird’s height, y metres, above the horizontal ground is given by 𝑦 = 1/4𝑡^4 − 𝑡^2 + 5 , 0 ≤ 𝑡 ≤ 4

Find the rate of change of height of the bird in metres per second when 𝑡 = 1

ii) Determine, with a reason, whether the bird’s height above the horizontal ground is increasing or decreasing when 𝑡 = 1

YEEEEEET Dec 2, 2018