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[?] ContourPlot 2 variables functions in W|A?

Posted 7 years ago

Hello i was testing out wolfram|Alpha for the first times with 2 variables functions and it seems that it's pretty inacurate.

As u can see in the image below, where i zoomed the contour plot, a point that is in clearly in the orange part has a lower value than a point clearly in the red part. it should be the contrary since the whiter the higher right ?

link to the wolfram page to see it in live

enter image description here

POSTED BY: ALEXANDRE SCHYNS
3 Replies

What was the meaning of the comma in your input? W|A interpreted it as a separator of a 2-vector. I wonder if this is what you really meant:

Plot3D[(472.5 + x)*(101.8 + y), {x, 0, 500}, {y, 0, 20}]
ContourPlot[(472.5 + x)*(101.8 + y), {x, 0, 500}, {y, 0, 20}]
POSTED BY: Gianluca Gorni

If you look closely at the "Input interpretation", you will see that W|A has interpreted your input as the plot of the dot product of two vectors, not as the product of two linear polynomials. Try using US-style decimal numbers:

Plot3D[(472.5+x)*(101.8+y), {x, 0, 500}, {y, 0, 20}]
POSTED BY: Michael Rogers

wow thanks a lot i didnt know a dot instead of a coma could put me in trouble like this ! as i said i'm new with this tool ! have a great day

POSTED BY: ALEXANDRE SCHYNS
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