#1

Alright fellow UGers, I am currently learning in math how to use limits to find tangents. I am horribly confused. If someone could show me how to do the following question, I would be grateful

Find the slope of the tangent to the curve at the given point:

y = 1/x at (2,1/2)

using the formula -- (f(x) - f(a)) / x-a preferably plz

(the answer is -1/4 according to the back of the textbook)

thx in advanced

pepsi :liplickL

:

Find the slope of the tangent to the curve at the given point:

y = 1/x at (2,1/2)

using the formula -- (f(x) - f(a)) / x-a preferably plz

(the answer is -1/4 according to the back of the textbook)

thx in advanced

pepsi :liplickL

:

#2

Alright fellow UGers, I am currently learning in math how to use limits to find tangents. I am horribly confused. If someone could show me how to do the following question, I would be grateful

Find the slope of the tangent to the curve at the given point:

y = 1/x at (2,1/2)

using the formula -- (f(x) - f(a)) / x-a preferably plz

(the answer is -1/4 according to the back of the textbook)

thx in advancedpepsi :liplickL

:

Boy that really backfired eh?

#3

u in alg. II?

cause i'm in geometry, and i don't think i know how to do that.

cause i'm in geometry, and i don't think i know how to do that.

#4

It's sad that I did this stuff in Calculus no less than a month and a half ago, and I can't remember how to do it.

#5

Y=1/x

f(x)-f(a)/x-a

lim(xapp2) [(1/2)-(1/x)]/[x-2]

lim(xapp2)[(x-2)/2x]/[x-2]

simply fraction (x-2)/2x X -1/(x-2)

lim(xapp2)[-1/2x]

plug in limit. m=-1/4

f(x)-f(a)/x-a

lim(xapp2) [(1/2)-(1/x)]/[x-2]

lim(xapp2)[(x-2)/2x]/[x-2]

simply fraction (x-2)/2x X -1/(x-2)

lim(xapp2)[-1/2x]

plug in limit. m=-1/4

#6

did it like a month ago.you lucked out that i remembered.

#7

It's sad that I did this stuff in Calculus no less than a month and a half ago, and I can't remember how to do it.

agreed

#8

**Differentiation!**

Two ways to do it. You might just find out that ( 1/(x+Δx) - x )/Δx approaches -1/x^2 as Δx approaches zero, and then sub 2 into -1/x^2, giving you -1/4, OR you could sub 2 in for x (but not Δx) at the top, giving you the same answer.

Your formula is dumb.