# Thread: urgent HW help

1. ## urgent HW help

Q.1 Use Newton’s method to find the value of x for the function
f(x)=2x^2+4x-3=0 ; x>0

Note: Perform only 3 iterations.

Q2 and Q3 in attachment

thanks in advance

2. ## Various problems

Hello
Originally Posted by ea12345
Q.1 Use Newton’s method to find the value of x for the function
f(x)=2x^2+4x-3=0 ; x>0

Note: Perform only 3 iterations.

Q2 and Q3 in attachment

thanks in advance
You don't say where the problems lie, so I'll just give you some general hints.

1 $\displaystyle f'(x)=4x+4$

Try, say, $\displaystyle x_1=1$ as a first approximation, and then use

$\displaystyle x_{n+1} = x_n-\frac{f(x_n)}{f'(x_n)}$ to get the second and third approximations.

2 Use the substitution $\displaystyle 1+\sin x = u$. Very straightforward.

3 Image too small to read fully, but it looks as though you need to expand $\displaystyle k(k-2)(k+2)$ to get $\displaystyle k^3-4k$, and then sum these two terms separately.

Grandad

3. plz step by step solution

4. Originally Posted by ea12345
plz step by step solution
You've been given help to get started. Having carefuly read and thought about this help (I assume), you now need to be much more specific than the above statement.

Please explain what you've tried and where you get stuck.

5. Originally Posted by ea12345
Q.1 Use Newton’s method to find the value of x for the function
f(x)=2x^2+4x-3=0 ; x>0

Note: Perform only 3 iterations.

Q2 and Q3 in attachment

thanks in advance
See here also: http://www.mathhelpforum.com/math-he...ns-method.html

Thread closed.