# calculus

posted by on .

Hi, I have online homework for calculus and I have to input two equations that will describe this graph. I have an image but Jiskha won't let me link to any websites... if this is allowed the URL to the image of the graph is

img145.imageshack.us/ img145/1787/80193630 .png

without the spaces.

f(x)= _______ for x in the interval [ ___ to ___]
f(x)= _______ for x in the interval [ ___ to ___]

Personally, I tried

f(x)= 3/2x+2 for [-2,2]
f(x)= -3x for [2,4]

The intervals are correct but the equations are not. Can someone help me with this?

• calculus - ,

Oops, for the interval of the first one it's [-5,2]. Typo.

• calculus - ,

I was able to see your diagram.
Your slope for the first one is incorrect
(2,5) to ((-5,-5) has slope -10/-7 = 10/7
so y = (10/7)x + b
for (2,5)
5 = 20/7 + b
35 = 20 + 7b
b = 15/7

equation : y = (10/7)x + 15/7

the second equation:
slope is correct
so y = -3x + b
using (2,5)
5 = -6 + b
b = 11
equation: y = -3x + 11

• calculus - ,

Thank you very much. I think somewhere between wrong slopes and a mix-up in the point-slope form equation, I messed up the equations. But I got it now. Thanks a lot!