Question

For a cosine function with amplitude A=0.75 and period T=10, what is y(4)?

Answer 1

2π/T = 2π/10 = π/5

y(x) = A sin (wx) = 0.75 sin (πx/5)

y(4) = 0.75 sin (4π/5) = 0.4408389392... ≈ 0.441

Answer 2

y(4) = -0.606

Step-by-step explanation:

Given that,

The amplitude of cosine function, A = 0.75

Time period, T = 10

The cosine function is given by :

`y=A\ cos(\omega t)`

Since,
`\omega=(2\pi)/(T)`

`y=A\ cos((2\pi)/(T)t)`

`y=0.75\ cos((2\pi)/(10)t)`

We need to find y (4). Put t = 4 in above equation as :

`y(4)=0.75\ cos((2\pi)/(10)* 4)`

y(4) = -0.606

Hence, this is the required solution.