## sabika13 3 years ago I need some serious help please :(.. Make a summary table with these headings shown for each graph: Interval, Sign of Function, Sign of Slope, Change in Slope I dont know how to figure out these??

1. sabika13

this is the graph i got with the question : pic.twitter.com/7aVfNYi4

2. sabika13

here, can u see this?

3. mark_o.

Interval Table X Y -4 close to zero -2 0.2 0 1 0.5 2 1 Infinity 2 1 3 0.2

4. sabika13

at the back of the book, the intervals are x<1 and x>1

5. sabika13

i understand the intervals, but not the rest of them like sign of slope..

6. mark_o.

sign of functions f(x)= infinity, if x=1 f(x)=1 to infinity, if interval is from 0<x<1 f(x)=infinity to 1, if interval is from1<x<2 f(x)=1 to approach zero, if interval is from x>2 f(x)=1 to approach zero, if interval is from x<-2

7. sabika13

where did you get 0.25 and 0.2 from?

8. mark_o.

sign of slope and change of slope y2- y1 slope m=------- x2 - x1 from interval [-2,-1], f(-2)=0.2 , f(-1)=0.25 therefore 0.25-0.2 0.05 0.05 m1=-----------=--------= --------= 0.05 positive slope here -1-(-2) -1+2 1 from interval [-1,0], f(-1)=0.25 f(0)=1 0.25-1 -0.75 m2=---------=-----------= +0.375 still positive here -1-1 -2 the slope here is increasing from positive 0.05 to 0.375

9. mark_o.

look at the graph x=-1, y=f(-1)=0.25 x=-2, y=f(-2)=0.2

10. mark_o.

those are only approximation and assumption only to be able to know if you are on positive or negative slope changing decreasing or increasing

11. mark_o.

but if the sign is change from positive to negative it is decreasing function and from negative to positive sign it is increasing functon

12. sabika13

ohhh it makes sense!! and then you do the same thing to the other side right, because what you did was x<1 (for slope) and then I do x>1 ?

13. mark_o.

next try that from interval [2,1] or from x=2 and x=1 find f(2)=? , and f(1)=? then find out if it is increasing or dec

14. mark_o.

yeah......try that

15. sabika13

okay so f(2)=1 and f(3)=0.25 Slope= 0.25 - 1 / (3-2) = -0.75 f(3)= 0.25 f(4)= 0.02 slope= 0.02-0.25 / (4-3) =-0.23 Negative and decreasing!!! :D

16. sabika13

Thank you so much!!

17. mark_o.

yessssss....good luck now and enjoy lol :D

18. mark_o.

YW