Applying a negative to the function to find the maximum

hello to find the maximum point in a curve I must use the negative function however this creates errors. My function is f = @(x)p1*x^4 + p2*x^3 + p3*x^2 + p4*x + p5 where does the minus sign precede the f? Thanks.

Answer 1

[Titus Edelhofer]

Hi,

your minus should span the entire function, i.e.

f = @(x) -(p1*x^4 + p2*x^3 + p3*x^2 + p4*x + p5);

Titus

Answer 2

[Steven Lord]

If you don't want to recreate the function handle as Titus suggested, create a new function handle that calls the existing function handle and negates that function's output:

 minusF = @(x) -f(x);

Answer 3

[Azzi Abdelmalek]

f=@(x)p1*x^4+p2*x^3+p3*x^2+p4*x+p5
h=@(x)-f(x)

Answer 4

[Gavin Seddon]

Many thanks for all these answers; this was what I was after Titus. I will implement your suggestion Stephen. Thank you again.

Answer 5

[siscovic]

Hello, how to calculate the gradient, Hessian matrix, of this function.Thank you

f=@(x) (x(1)-2)^4+(x(1)-2)^2*x(2)^2+(x(2)+1)^2