Hello guys , please help me ! I

I have two vectors :

x= [1 2 3 4 5 6]

and

y=[2.3 4.3 5 4.7 9 12]

and i need to find the value of y in x = 3.5

[James Tursa]

Is this an interpolation question? Or ...?

[Dombrovschi Andrei]

nope ...

[Rik]

Then what is it?

[Dombrovschi Andrei]

I want to see the value of y in time x = 3.5 per graph

[Dombrovschi Andrei]

x= [1 2 3 4 5 6]
y=[2.3 4.3 5 4.7 9 12] 
figure
plot(x,y,'r-')
value = xx==3.5(find(y));

hold on
plot(3.5,value,'r*')

[per isakson]

Isn't that interpolation

>> interp1( x, y, 3.5 )
ans =
    4.8500

Answer 1

[Star Strider]

It is an interpolation, regardless of the method you want to use. There are likely several ways to do this.

Using interp1:

x = [1 2 3 4 5 6];
y = [2.3 4.3 5 4.7 9 12];

idx = find(x <= 3.5, 1, 'last');
yi = interp1(x(idx:idx+1), y(idx:idx+1), 3.5, 'linear')

yi =
     4.8500

If you want to use the 'previous', 'next', or 'nearest' methods instead of 'linear', the results are 5, 4.7, and 4.7 respectively.

Answer 2

[Dombrovschi Andrei]

thanks guys !

[Star Strider]

Our pleasure!