Question

x = 5cos (2πt + π/4). at t = 1.5s find amplitude

Answer 1

Answer: - 5/(√2)

Explanation: on putting t = 1.5 second in the given equation the equation will look something like

X = 5cos ( 3π + (π/4))

=> X = 5cos ( π + 2π + 45°)

[ π radians = 180° ]

=> X = 5cos ( π + 45° )

Or, X = - 5 cos45°[cos(180-¢)= -cos¢]

So, X = - 5/(√2)