To solve this problem using Newton's Method, we need to iteratively calculate xn using the formula:
xn+1=xn−f′(xn)f(xn)
Step 1: Define f(x) and f′(x)
The function given is:
f(x)=ex−2x−4
The derivative is:
f′(x)=ex−2
Step 2: Start with x0=0
We are given the initial guess x0=0. Now we compute the next approximations.
Iteration 1: Compute x1
x1=x0−f′(x0)f(x0)
Substitute x0=0 into f(x) and f′(x):
f(0)=e0−2(0)−4=1−4=−3
f′(0)=e0−2=1−2=−1
x1=0−−1−3=0−3=−3
Iteration 2: Compute x2
x2=x1−f′(x1)f(x1)
Substitute x1=−3 into f(x) and f′(x):
f(−3)=e−3−2(−3)−4=e−3+6−4=e−3+2
f′(−3)=e−3−2
Using a calculator:
e−3≈0.0498
f(−3)≈0.0498+2=2.0498
f′(−3)≈0.0498−2=−1.9502
x2=−3−−1.95022.0498≈−3+1.0513=−1.9487
Iteration 3: Compute x3
x3=x2−f′(x2)f(x2)
Substitute x2=−1.9487 into f(x) and f′(x):
f(−1.9487)=e−1.9487−2(−1.9487)−4
f′(−1.9487)=e−1.9487−2
Using a calculator:
e−1.9487≈0.1420
f(−1.9487)≈0.1420+2(−1.9487)−4=0.1420−3.8974−4≈−1.7554
f′(−1.9487)≈0.1420−2≈−1.858
x3=−1.9487−−1.858−1.7554≈−1.9487+0.9447=−1.0040
Final Answers:
x1=−3.00000,x2=−1.94870,x3=−1.00400
Would you like detailed explanations for these steps or assistance with other related concepts?
5 Questions to Explore Further:
- What are the theoretical foundations of Newton's Method?
- How does the choice of the initial guess (x0) affect convergence?
- Can Newton's Method fail to converge? If so, under what conditions?
- How does this method compare with other root-finding algorithms (e.g., bisection)?
- Can we use Newton's Method for systems of equations? How?
Tip: Always ensure the derivative f′(x)=0 at any point during Newton's Method to avoid division by zero.