Question

*matlab*

Hi, for the plotting of question C, the correct answer is the first curve graph when i use yp=alpha*xp^beta. why cant i use polyval for this?

The solubility of oxygen in water S, is a function of the water temperature T. The solubility of O2 as millimoles of O2 per litre of water has been measured for several temperatures as shown in the table below. It is believed that the data follows the power relationship. i.e. S-: αΤβ where α and β are coefficients S (mmol O2 /L H20) 1.95 1.70 10 1.55 15 1.40 20 1.30 25 1.15 30 1.05 35 1.00 40 0.95 45 A. Show by hand with pen and paper the linearisation of this nonlinear model. You will need to present this work for marking B. Use the linreg() function in MATLAB to ultimately determine the non-linear coefficients α and β and the r2value. Print the non-linear equation and r value C. Plot the raw data as blue circles. Use the non-linear function to interpolate/extrapolate the solubility values for temperatures ranging 0°C to 60°C, and then plot this as a black continuous line on the same figure D. Determine the solubility of O2 in water at a temperature of 50°C and plot this as a red diamond on the same figure. Print the non-linear equation as the title of the plot %date modified 7/5/19 clear all: close all; clo a.s T " 1 5:5:45]'; S1.95 1.78 1.55 1.48 1.30 1.15 1.85 1.00 .951 ae,a1,r21inreg(Log(T), Log(S) beta # a1 Lpha explae) r2er2 fprint f("The non-linear equation is S " alphaeT^beta, and the r^2 value i$ %nn., r2) plot (T,S, 'bo hold on label(' T4 degree) ., ylabel( Solubility of oxygen titlel SalphasT beta ppolyfitilog1e(T), Logle(S),1) yp alpha*xp."beta yp-polyval(p,xp) plot (xp, yp, 'k-') bdate nodified 7/5/19 clear alli close all; cle -1 5:5:451 S -1.95 1.70 1.55 1.48 1.30 1.15 1.«5 1.00 8.951 ae,a1,r21inregltog(T), log(S)) beta-a1 alpha expla) r2 r2 fprintf( The non-1inear equation is s alpha T beta, and the r2 value is fn,r2) plot(T,S, 'bo hold on xlabel( T(degree) ylabel( Solubility of oxygen titlel's # alpha,-beta. p polyfit log1(T),log10(S), yp alphaexp. "beta yp polyval(p, xp) plot (xp, yp,'k-')

Answer 1

EXPLANATION:
yp = alpha*xp^beta

log yp = log alpha + beta * log xp

Y = MX + C

Y = log yp

M = beta

C = log alpha

X = log xp

if you use these equation and polyfit 1 degree equation and use its parameters, then you can use polyval for correct answer.