Recent content by aziqbal

arrghh thanks so much guys, yes i need to round especially the first co-efficient to many decimal places and it works fine then! thanks again!

Just used those 4 points that's all It's been fitted by numerous other members to the 3rd order polynomial and that's the right equation But just take 120 as the x value and enter it in and you get a different y value?? Here's a worked example 0.0001(120^3)...

ok thing are working well now i think i have this sorted however i had one question, when i plot the following data set for x,y 0,280.32 60,437.03 120,441.10 180,434.34 i get a curve, that best fits to a 3rd order polynomial which is this equation y=0.0001x^3 - 0.0409x^2 + 4.6716x +...

OMG I just did 4 pages of Maths and got x to be -42.76! Could I push my luck and ask if anyone else got a value close to that?? That equation is really tough so many steps I had to split it into parts and do each part individually

Ok that's great! So basically if I want to solve for zero if I plug my co-efficients into the above equation I should get value for x So putting in A=0.0001 B= -0.0409 C=4.6716 D=280.32 Into the above I should get out a value for x? Just want to make sure before I attempt as...

Thanks Ray I will give it a go I was just thinking of it another way if I solve for x using the cubic root method using the following equation, this is from wiki Where do I enter in my y value in all of this? I'm assuming this is solved for y=0

How did you get this x value of -1.27... The ranges I gave were rough estimates of the ranges I'm interested in If I enter 100 as my x value I get 438.32 for the y value that's great! But I know only the y values and need to calculate my x values So for example what is the x value when my y...

No, no integers Ok so that means I have 3 possible roots for this equation which means for each y I wil, have 3 values of x?? That's ok because I know what range my x values need to be so I can just take which x value I need That's a long way and a lot of calculations I need to enter but I...

My bad I got confused with the integer issue ok ignore that! My problem still stands, yes I need to calculate a series of x values based on a series of y values ranging from 275-475, I can not believe how hard this has turned out to be How come I can put in a x value and read out a y value...

Ok great I used Wolfram a great website to get this part but I don't get what the n=z part means So I guess this is telling me there is 3 possible solutions to this equation, in my case I know what my y values are and need to back calculate my x values

Yes basically I have plotted the graph but want to have it so I can enter in the y values and read out the x values I am restricted by using excel only so I don't know if that will hinder the progress The wiki page that is posted in the link, I don't really get, is that saying that I can...

i for got to add I have a set of Y values between (275-475)and I need to back calculate a set of x values X values should be between 0-180

sorry the whole thing i do not know how to solve this equation for a particular y value i need to find out what the x is? basically solving for equation =0 so if i have y=100 what is x=?

hi i need some help solving this equation for x y=0.0001x^3-0.0409x^2+4.6716x+280.32 can someone please help me, i really need to solve this for x! full layout would be great many thanks!