Given this set of data, is it possible to perform a 2nd order curve fit with the set constraint that the leading coefficient must be positive? Using an unconstrained curve fit (both "polyfit" and "fit" were used), the data produces a curve with a rather small negative leading coefficient. For reference, the data is as follows:
x = 150, 190, 400, 330, 115, 494
y = 1537, 1784, 3438, 2943, 1175, 4203
The given outputs using both methods largely agreed, as shown below:
fit_eq =
-0.0007 8.3119 255.8074
eq =
Linear model Poly2:
eq(x) = p1*x^2 + p2*x + p3
Coefficients (with 95% confidence bounds):
p1 = -0.0007088 (-0.003588, 0.00217)
p2 = 8.312 (6.51, 10.11)
p3 = 255.8 (25.01, 486.6)Given this set of data, is it possible to perform a 2nd order curve fit with the set constraint that the leading coefficient must be positive? Using an unconstrained curve fit (both "polyfit" and "fit" were used), the data produces a curve with a rather small negative leading coefficient. For reference, the data is as follows:
x = 150, 190, 400, 330, 115, 494
y = 1537, 1784, 3438, 2943, 1175, 4203
The given outputs using both methods largely agreed, as shown below:
fit_eq =
-0.0007 8.3119 255.8074
eq =
Linear model Poly2:
eq(x) = p1*x^2 + p2*x + p3
Coefficients (with 95% confidence bounds):
p1 = -0.0007088 (-0.003588, 0.00217)
p2 = 8.312 (6.51, 10.11)
p3 = 255.8 (25.01, 486.6) Given this set of data, is it possible to perform a 2nd order curve fit with the set constraint that the leading coefficient must be positive? Using an unconstrained curve fit (both "polyfit" and "fit" were used), the data produces a curve with a rather small negative leading coefficient. For reference, the data is as follows:
x = 150, 190, 400, 330, 115, 494
y = 1537, 1784, 3438, 2943, 1175, 4203
The given outputs using both methods largely agreed, as shown below:
fit_eq =
-0.0007 8.3119 255.8074
eq =
Linear model Poly2:
eq(x) = p1*x^2 + p2*x + p3
Coefficients (with 95% confidence bounds):
p1 = -0.0007088 (-0.003588, 0.00217)
p2 = 8.312 (6.51, 10.11)
p3 = 255.8 (25.01, 486.6) curve fitting, matlab, polyfit MATLAB Answers — New Questions

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