Question

will pay with eternal gratitude

f(x)= (3x^2)/[(4-5x)^5]
find the equation of the line tangent to the graph of f at x=2.

f(x)=5x[(5-5x)^(1/2)] find the equation of line tangent to the graph of f at x=-2

Answer 1

Find derivative.

Answer 2

Yeah, I get up to there. I need it in y=mx+b form though

Answer 3

Then find f'(2) or evaluate derivative at 2. And f(2) or evaluate function at 2. Your y-mx+b actually look like this [f'(2)](x-2)] + f(2)

Answer 4

at 2 I get .00489 for the first one. It's the intercept I'm having trouble with.

Answer 5

I don't know what you mean exactly. Please explain.

Answer 6

ok, so for the first one, I get 3x(15x+8)/((4-5x)^6) as my derivative. At x=2, my value is .00489. so I have y=.00489x+?

Answer 7

so it's that last part that I can't get

Answer 8

The 'last part' is your original function, wheve ever there is x, plug in 2. (Evaluate original function at 2)

Answer 9

plus I typed I wrong equation, it's 3x^3, not 3x^2. In which case ((6x^2(5x+6))/((4-5x)^6) is my derivate

Answer 10

Possible mistake with derivative\[f'(x)=[6x(4-5x)^{5}+75x ^{2}(4-5x)^{4}]/(4-5x)^{10}\]

Answer 11

Start over. Open up a new question. Write the correct question and write only one question at a time.

Answer 12

good idea

Answer 13

\[f'(x)=[9x ^{2}(4-5x)^{5}+75x ^{3}(4-5x)^{4}]/(4-5x)^{10}\]