Question

Find the slope of the tangent line to the curve 2x^4-3x^2+sq.x-5/x^2 at point (1,-5)

Answer 1

is the x^2 the denominator of everything else?

Answer 2

no just the denominator of 5

Answer 3

ok...so the last term is 5/x^2 everything else is as is..

Answer 4

i was thinking about rewriting it as 5x^-2, but i'm not sure

Answer 5

correct

Answer 6

go ahead, its all good :)

Answer 7

ook cool

Answer 8

8x^3 -6x +(1/2sqrt(x)) +(10/x^3) is what i get... maybe its right?

Answer 9

yea i got 8x^3-6x+1/2x^-1/2-10x^-3, should i substitute after this?

Answer 10

yep, but I think you only need the "x" value

Answer 11

8 -6 + (1/2) +10

Answer 12

yea so just substitute the x value

Answer 13

and youve got a typo,,,that last term should be a (+); -5(-2)=10

Answer 14

oh yea thanks

Answer 15

I get 6 as the slope... if I did it right :)

Answer 16

uhm i'm not sure if we're doing it right cuz the problem is actually asking me for the equation of the line

Answer 17

the derivative is the equation of the slope of the line; or maybe it should be in y = mx+b format?

Answer 18

yea i think that's what they mean y=mx+b format

Answer 19

y = 6x +b at (x=1,y=-5)??

-5 = 6(1) + b

-5 = 6 + (-11)

y = 6x-11 then

Answer 20

hold up, how did u get 6 as the slope, i'm up to 8-6+1/2+10

Answer 21

f'(x) = m

8-6=2+10=12...ahhh, I see; I multiplied by 1/2

Answer 22

12.5 happy :)

Answer 23

ook cool

Answer 24

lol

Answer 25

-5 = 12.5(1) + b

-5 -12.5 = b

-17.5 = b

y = 12.5 - 17.5...

Answer 26

squeeze an "x" right up next to that 12.5

Answer 27

or do they want it in Ax + By = C format?

Answer 28

y=mx+b format

Answer 29

you can use the line equation to figure out a new "x value" when iterating a function solve it...

Answer 30

uhm not sure about that... does that mean that y=6x-11 is not it

Answer 31

yeah, since i miscalculated the first time with a "6", its a bad apple...toss it out before it spoils the rest :)

Answer 32

ook

Answer 33

ok then it's 8-6+1/2+10=12+1/2=25/2

Answer 34

so the slope is 25/2

Answer 35

got it thanks :)