Of the infinitely many lines that are tangent to the curve y = −5 sin(x) and pass through the origin, there is one that has the largest slope. Use Newton's method to find the slope of that line correct to six decimal places.

Respuesta :

Answer:

The slope is 1.086168

Step-by-step explanation:

* Lets explain how to solve the problem

- The slope of any curve y = f(x) is dy/dx

- The slope of the line which passes through the origin and the point

 (x , y) is y/x

* Lets solve the problem

∵ y = -5 sin(x)

∵ m = dy/dx , where m is the slope of the tangent to the curve

- The differentiation of sin(x) is cos(x)

m = -5 cos(x)

∵ The tangent passes through the origin and a point on the curve

- The general point on the curve is (x , -5 sin(x))

∵ m = y/x

m = -5 sin(x)/x

∵ The slopes are equal

∴ -5 sin(x)/x = -5 cos(x)

- Multiply both sides by x

∴ -5 sin(x) = -5x cos(x)

- Divide both sides by -5 cox(x)

# Remember that sin(x)/cos(x) = tan(x)

∴ tan(x) = x

tan(x) - x = 0

* Lets use Newton's method

- In the Newton's method x(n+1) = x(n) - y/y'

∵ y = tan(x) - x

∴ y' = sec²(x) - 1

∵ sec²(x) - 1 = tan²(x)

x(n+1) = x(n) - [tan(x) - x]/tan²(x)

- Let x(1) = 4.5

∴ x(2) = 4.5 - [tan(4.5) - 4.5]/tan²(4.5) = 4.493614

∴ x(3) = 4.493409

∴ x(4) = 4.493409

∴ x(5) = 4.493409

∴ The value of x = 4.493409 is the largest value

∵ m = -5 cos(x)

∴ m = -5 cos(4.493409) = 1.086168

The slope is 1.086168