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## I want to identify wheter it is right

I am trying to express in case of 'variable two'

I tried to identify my answer wheter it is right by using excel.

But I don't know well. I think my answer is wrong.

Could you examine thath it is right?

I attached my files.

Thank you for reading my question

17 REPLIES 17

## Re: I want to identify wheter it is right

We cannot tell if you are doing something right if you don't tell us what you want to achieve!

You will have to explain what intend to do with your function xe(j). It seems that y2() is never user (ands its the same as x2() anyway and x and y will always be of same value. So it doesn't seem to make much sense to use y anyway.

In the meantime I had consulted my crystal ball to find out what may be after and I hope the attachment is of help.

## Re: I want to identify wheter it is right

 Werner Exinger wrote:We cannot tell if you are doing something right if you don't tell us what you want to achieve!You will have to explain what intend to do with your function xe(j). It seems that y2() is never user (ands its the same as x2() anyway and x and y will always be of same value. So it doesn't seem to make much sense to use y anyway.Why don't you use Google translate to help you to more clearly state what you want?In the meantime I had consulted my crystal ball to find out what may be after and I hope the attachment is of help.

Wow, maybe we need to collaborate our crystal balls

I was about to attempt this, but your attempt is nothing like I had in mind. A better explanation is required or at least the results he is expecting.

## Re: I want to identify wheter it is right

 jinsuk Lee wrote:I am trying to express in case of 'variable two'I tried to identify my answer wheter it is right by using excel.But I don't know well. I think my answer is wrong.Could you examine thath it is right?I attached my files.Thank you for reading my question

Are you trying to highlight the values of x2 which are less than the corresponding x value?

## Re: I want to identify wheter it is right

What jinsuk Lee is showing, sure is just a work in progress. He has asked similar questions before and I already pointed him to root and also to the solve block. But maybe because of a combination of lack of basic Mathcad knowledge and great difficulties to understand (my) English he(?) still sticks to his method of incrementing his variable by 0.1 until it exceeds a certain function value. Maybe he is doing this because it was the only way he found out doing it in Excel as his attached spreadsheet suggests.

As he is introducing two functions x2 and y2 now and obviously is solving for both variables x and y, I deduced (in fact my crystal ball did) he intends to change y2 to be different from x2 later and will then be searching for the values of x and y with x2()=x and y(2)=y which will give him some sort of threshold.

It sure would help if he could explain better what he is trying to achieve and what his goal is at the end, rather than posting an attempt and asking if its correct.

## Re: I want to identify wheter it is right

this file is my work.

I have experience difficult.

I mistake.

mu is 2/29, 3.5/29 ... 27.5/29, 29/29

## Re: I want to identify wheter it is right

You're trying to crate a vector of mu using i as an index. Your second mu in the list above is 3.5/29. so you asked i to be 1, 2.5 and so on. But 2.5 can't be a vector index, the index has to be integers.

But you have other problems: need to define phi, and a few other bits.

I've changed 1 thru 4 so they'll work, but Whether thet're correct . . . ?

## Re: I want to identify wheter it is right

I forgot CL, CD value definition.

CL is 1.04, CD is 0.08

## Re: I want to identify wheter it is right

Can it be that part of your homework is that you get yourself familiar with Mathcad? You sure haven't done that part as thourogh as you should have done and I strongly suggest that you catch up on that. Learn about ranges and vectors, function definition and their dependencies and the possibilities Mathcad offers to numerically solve system of equations (solve block). You may look up some features in the built-in help (which is incomplete and very uncomfortable to navigate) or use whatever resource you can lay your hand on.

Then you may start by correctly defining your functions considering their dependencies, beginning with

Then go on with sigma, H, g1 and g2. Notice that g1 and g2 will be dependend on 5 arguments.

Then create a solve block to solve your two equations a=g1/(1+g1) and a'=g2/(1+g2) for a and a' and turn this solve block into a a function depending on a mu, r and c by typing res_(mu,r,c):=Find(a,a') at the end of the block. res_ ist just an arbitrary function name I had chosen.

Now you can solve for a and a' for any given triple of mu, r, c.

Only now is the time to define vectors for mu, r, and c which can be done in various ways

or you first define just r and then its easy to calculate mu and c with r.

Don't let mu run up to 1 because Phi will be zero, sin(Phi)=0, too, and you get a division by zero when calculating f.tip.

No you can call your function res_() with the three vectors as arguments, vectorize the call and the result is a nested vector consisting of 2x1 matrices.

If you have troubles separating the a and a' values, post your sheet and ask again.

At the end you should be able to create a table like the following. Only if my crystal ball was right about what you are really searching for and I am also not sure if I have interpreted or you haven given your functions correctly.

Hope you understand that we won't do your complete homework here as this would render that homework useless, especially for you yourself.