Question

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

Answer 1

eq of the tangent is:
y-f(2)=f'(2)(x-2)
Do u know how to solve it now?

Answer 2

No, I get m, but not b

Answer 3

for x=2, the value I get is .00823, unless I have the wrong derivative.

Answer 4

it's very easy..try again,first find f(2) bu replacing 2 instead of x in the eq given.then find the derivative of the eq and find f'(2)
and then replace the values u found

Answer 5

[U/V]'=(U'V-UV')/V^2

Answer 6

ok, so for my derivative I have (6x^2(5x+6))/((4-5x)^6)

Answer 7

You made a mistake on the derivative, go to your other post, I wrote the derivative there.

Answer 8

Also, depending on your teacher, but generally in these types of problems, it is not necessary to find decimal numbers, leave them in fractions.

Answer 9

It's an online assignment, so it requires 4 decimal places. Are you sure about your derivative.

Answer 10

Take the denominator for example, it is\[[(4-5x)^{5}]^{2}=(4-5x)^{10}\]

Answer 11

why are you squaring the denominator?

Answer 12

In the process of finding the derivative, you use a process call the quotient rule. It is usually written like this\[(u'v -uv')/v ^{2}\]

Answer 13

\[u =3x ^{3}\]\[u'=9x ^{2}\]\[v =(4-5x)^{5}\]\[v'=-25(4-5x)^{4}\]

Answer 14

Is this making any sense?

Answer 15

somewhat.