Thread: gradient

hi people, my question is: find the gradient of the curve

a) at the point where the curve crosses the y axis
and
b) at each of the points wherethe curve crosses the x axis

for a) i differentiated (i think thats what you call what i did) like this:
then made x = 0 as would be the case with the y axis and came up with - 2 which i know is right

but for b) i made y = 0 and used the quadratic formula for x.

and came up with x = 6 or x = -4

the answer for b) written in my textbook is -10, 10

can someone show me how i'v gone wrong please?

thankyou

ah sorry i've just realised how i need to finish that and its pretty simple haha. sorry for wasting your time.

Originally Posted by mark

ah sorry i've just realised how i need to finish that and its pretty simple haha. sorry for wasting your time.

I assume you substituted x = 6 and x = -4 into dy/dx ....

yep, thats what i did