Question

G is a trigonometric function of the form g(x)=a sin(bx+c)+d The function intersects its midline at (-1,6) and has a minimum point at (-3.5,3). Find the formula for g(x). Give an exact expression.

Answer 1

Answer:

g(x) = 3*sin((-15/4)*pi*x + (-15/4)*pi) + 6

Step-by-step explanation:

The function has the form:

g(x) = a*sin(b*x + c) + d

We know that:

The midline is at (-1, 6)

The midline is the value of g(x) when the sin(x) part is equal to zero

Then the midline is y = 6 = d

g(x) = a*sin(b*x + c) + 6

And from this we also know that:

sin(b*-1 + c) = 0,

We also know that the minimum is at (-3.5, 3)

The minimum is the y-value when the sin(x) part is equal to -1

Then

sin(b*-3.5 + c) = -1

And:

g(-3.5) = 3 = a*(-1) + 6

3 = -a + 6

a = -3 + 6 = 3

The equation is something like:

g(x) = 3*sin(b*x + c) + 6

To find the values of b and c, we need to use the two remaining equations:

sin(b*-3.5 + c) = -1

sin(b*-1 + c) = 0

We also know that:

Sin(0 ) = 0

sin( (3/2)*pi) = -1

where pi = 3.14

Then we can just write:

b*-1 + c = 0

b*-3.5 + c = (3/2)*pi

From the first one, we get:

-b + c = 0

c = b

Replacing that on the other equation we get:

c*-3.5 + c = (3/2)*pi

c*(-3.5 + 1) = (3/2)*pi

c*(-2.5) = (3/2)*pi

c = (3/2)*pi/(-2.5)

and:

-2.5 = -5/2

c = (3/2)*(-5/2)*pi = (-15/4)*pi

Then the equation becomes:

g(x) = 3*sin((-15/4)*pi*x + (-15/4)*pi) + 6

Answer 2

Answer:

3sin(pi/5 x +pi/5)+6

Step-by-step explanation: