Newton-Raphson Formula question

[synkk]

Question:
Find the smallest positive root of the equation x^4 + x^2 - 80= 0 correct to two decimal places. Use the Newton-Raphson process.

How would I go about finding the smallest positive root? What I was thinking is using x = 3 as x = 3 is the largest number that would be close to 0 (for the equation), then finding an approximation for that, is that correct?

thanks.

 

[PAllen]

1) Independent of the question asked, can you see that the equation is trivially solvable exactly analytically (no need for Newton-Raphson)?

2) For a numeric solution, a start value of 3 looks fine. I assume (hope) you know how to apply Newton-Raphson from there.

 

[synkk]

1) Independent of the question asked, can you see that the equation is trivially solvable exactly analytically (no need for Newton-Raphson)?

2) For a numeric solution, a start value of 3 looks fine. I assume (hope) you know how to apply Newton-Raphson from there.

I'm perfectly aware it is solvable from that form, and I do know how to apply Newton-Raphson. Thanks.