Answer:
Here we have the position of an object represented by the equation:
y = 4*sin(3*x) + 4
Where we can assume that y represents the height of the object.
We want to find the maximum height of the object, and for which value of x it happens in the interval 0 ≤ x ≤ 5
First let's find the maximum height.
y = 4*sin(3*x) + 4
Here the only variation is on the sin( ) part, we know that the maximum value of the sin(x) function is:
sin(x) = 1
when x = 90° = pi/2 = 3.14/2
Replacing that in the equation, we get:
y = 4*1 + 4 = 8
The maximum height of the object is 8.
Now, we know that the maximum of the sin(x) function is when x = pi/2
But in our case, we have the function sin(3*x)
Then this function is maximized when:
3*x = pi/2
x = pi/(2*3) = pi/6 = 3.14/6
And:
0 < 3.14/6 < 5
Then the first maximum occurs at x = 3.14/6 = 0.52
But it can happen again on the interval.
The next maximum of the sin(x) function is when:
x = pi/2 + 2*pi
In our case, we again have sin(3*x), then we need to solve:
3*x = pi/2 + 2*pi
x = (pi/2 + 2*pi)/3 = (3.14/2 + 2*3.14)/3 = 2.62
This is also in the interval 0 < x < 5
The next maximum of sin(x) happens at:
x = pi/2 + 2*pi + 2*pi
In our case, for sin(3*x) we need to have:
3*x = (pi/2 + 2*pi + 2*pi)
x = (3.14/2 + 2*3.14 + 2*3.14)/2 = 4.71
This again is in the interval 0 < x < 5
(is closer to the upper value, so we can expect that the next maximum does not belong to the interval)
Then the maximum height occurs at:
x = 0.52
Then occurs again at:
x = 2.62
And finally occurs again at:
x = 4.71
