[Tutor] Expecting a float but get an int

[Alan Gauld]

On 23/05/2021 08:28, Phil wrote:
> Help please.
> 
> This function returns "a" as .7 and "b" as 0 instead of .7. I'm sure the 
> reason is obvious but I cannot see what it is.
> 
> def slope_intercept(x1, x2, y1, y2):
>      a = (y2 - y1) / (x2 - x1) # a = .7 which is correct

It is not correct.
It should be (using your values) 0.7777777....
Or more accurately it is the rational number 7/9

>      b = (y1 - (a * x1) # b = 0 where it should be .7

And this is 7 - (7/9) * 9 = 7-7 = 0

> slope, intercept = slope_intercept(9, 0, 7, 0)

The real mystery is how you get 0.7 for a...

> What have I overlooked?

Math.


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