# Rachel Ong

**Statistics**

**MATLAB Answers**

**17** Questions

**0** Answers

RANK**254,600**

of 257,731

REPUTATION**0**

CONTRIBUTIONS

**17** Questions

**0** Answers

ANSWER ACCEPTANCE **
47.06%
**

VOTES RECEIVED**0**

RANK

of 17,762

REPUTATION**N/A**

AVERAGE RATING**0.00**

CONTRIBUTIONS**0** Files

DOWNLOADS **0**

ALL TIME DOWNLOADS**0**

RANK

of 109,971

CONTRIBUTIONS

**0** Problems

**0** Solutions

SCORE**0**

NUMBER OF BADGES**0**

CONTRIBUTIONS**0 Posts**

CONTRIBUTIONS**0** Public Channels

AVERAGE RATING

CONTRIBUTIONS**0** Highlights

AVERAGE NO. OF LIKES

**Content Feed**

Question

Is it possible to do a search in a table for a value nearest to a number I want?

If I have an array of 100x2, is it possible to find the index of the row number nearest to a number I want? For example somethin...

2 months ago | 2 answers | 0

### 2

answersQuestion

I keep getting the solve stops prematurely for fsolve?

Why do I keep getting this error? I think the equations are solvable though? %% ROC ESTIMATION FOR PS = 3 WITH DIFFERENT THRUS...

2 months ago | 1 answer | 0

### 1

answerQuestion

Is this how I find the area under my graph?

I have this code which takes too long to run so I would save you the trouble and just attach a snippet of how I plotted the grap...

2 months ago | 1 answer | 0

### 1

answerQuestion

Why do I get the error saying I did not assign values to a call? I did assign my values after getting them from a function though? Anyone able to help me out and explain?

I got the script as attached below. I did assign T P rho and speedsound after getting it from the loop but I am getting the erro...

2 months ago | 3 answers | 0

### 3

answersQuestion

How do I interpolate to get the y axis values when I sub in the x axis values? My data is like a plot with no function associated to it.

I have a set of data points (an array, column 1 is for x values and column 2 is for y values) and I want to be able to sub in x ...

3 months ago | 1 answer | 0

### 1

answerQuestion

Hello, I am trying to solve the ODE but I have an error I do not understand how to solve. Would appreciate some help. Thank you!

I have this set of ode and I would like to solve it with ode45. I have this one variable deltae and this depends on the solution...

3 months ago | 2 answers | 0

### 2

answersQuestion

Solving a system of nonlinear equation using steepest descent for optimal control

Hello, anyone has an example on how I should use the steepest descent algorithm to solve for optimal controls with free final ti...

3 months ago | 0 answers | 0

### 0

answersQuestion

Hello. Anyone knows why the fminsearch does not work. Is it the way the code is structured ?

clear all clc S = 17.1 W = 1248.5*9.81 rho = 1.225 speedsound = 340.26 h = 0 % u = x(1) % CL = x(2) % x0 = [20,0]...

3 months ago | 1 answer | 0

### 1

answerQuestion

Problems on bvp4c solver because of its initial guess and a singular jacobian?

Hello, I have inputted what I can into the solver but I am missing the initial guess (I do not know how to do the initial guess ...

3 months ago | 0 answers | 0

### 0

answersQuestion

I need help understanding one line of the code for a 2pbvp. Also, anyone knows if there are other methods of writing the solinit part of the code?

I have this example here but I have problems understanding the code. If some one can help explain that to me I'll greatly ap...

3 months ago | 0 answers | 0

### 0

answersQuestion

Hello, when I am trying to solve my equations using dsolve, I get an empty sym for my dsolve.

The above is the equations I used to do my diferentiation wrt different states to get the hamiltonian equations for dsolve a...

3 months ago | 1 answer | 0

### 1

answerQuestion

Anyone knows how to solve this size compatibility issue? I got this from an example and I am trying to understand the script.

%% Solution Using Symbolic Toolbox (STB) in MATLAB Version 6.0 %% Example 2.14 pg 77 of NAIDU optimal control book --> not work...

3 months ago | 1 answer | 0

### 1

answerQuestion

I have an error where it says unrecognized function or variable x when using fsolve.

I have a variable that is called x(2) and I need to solve this using fsolve. However, variables like rho and speedsound are depe...

4 months ago | 1 answer | 0

### 1

answerQuestion

Hi, is it possible to have variables in an ode45 that varies according to another function?

This is my ode45 that I have to solve and, actually, the variables rho and speedsound (i have commented them out in the first sc...

4 months ago | 1 answer | 0

### 1

answerQuestion

I have an error but I dont know where it is referring to "Index exceeds the number of array elements"

This is my code for the intepreted MATLAB function on simulink function [XDOT] = RCAM_model(X,U) % ---------- State and co...

5 months ago | 0 answers | 0

### 0

answersQuestion

I have an error I got from using fsolve but I do not understand why.

clear all; clc; W = 1248.5*9.81; S = 17.1; K = 0.05; CDe = 0.03; h = 0; [T, p, rho, speedsound] = ...

5 months ago | 1 answer | 0

### 1

answerQuestion

I have an invalid use of operator error

function [T p rho] = atmos(h) h1 = 17; % Height of tropopause h2 = 20; % End height of table g = 9.81; R = 287; c ...

7 months ago | 1 answer | 0