Question

let f(x) = 2x^2-5x+9
a.Find slope of tangent line at x=2
b. Find an equation of the tangent line at x=2

Answer 1

I'm assuming you're in calculus? If so, the slope is the first derivate of the function.

Answer 2

Yes calc

Answer 3

The slope of your tangent line is the derivative.

Answer 4

I have no idea how to set this up

Answer 5

I have done problems like this though so I "know" how to do them and Ive done them before! thats whats frustrating lol

Answer 6

you can find the equation of the tangent line by doing y = mx + b form where y is the function of your tangent line, m = f'(2) the derivative at x=2, x is your independent varaible, and b is the y-int of the tangent line.

Answer 7

I'm telling you how to do (a).


1: Find \(\rm f'(x)\). Here, it is \(\rm f'(x) = 4x - 5\).
2: Evaluate \(\rm f'(x)\) for \(\rm x = 2\). Here, it is \(\rm 4(2) - 5 = 3\)

Answer 8

a. Calculate the derivate and calculate the value for x = 2
f'(x) = 4x -5
f'(2) = 4x2 -5 = 3

b. Calculate a point using f(x) and use that with the slope to calculate the formula for the line

f(2) = 7

point (2,7)
slope 3

y = ax + b
7 = 3 times 2 + b
7 = 6 + b
b = 1

y = 3x + 1

Answer 9

Ok thanks everyone Im going through this now

Answer 10

where did the 4x-5 come from ? for the derivative?

Answer 11

it's the derivate of your function ->
2x^2 => 4x
-5x => -5

Answer 12

I guess I don't know how to do that

Answer 13

You had best google it or open your book

Answer 14

already there, problem is Im sick and this cold medicine is blocking my memory right now I can't form a thought properly thats why I can't do this

Answer 15

Well, i can't really help you understand either then, use the answer i gave you, get better and study :)

Answer 16

ok the power rule, jesus :P I got it

Answer 17

ghehe

Answer 18

thanks everyone