English Deutsch Français Italiano Español Português 繁體中文 Bahasa Indonesia Tiếng Việt ภาษาไทย
All categories

5 answers

f''(x) = x+2

Integrate this to obtain f'(x)
f'(x) = S(x+2)dx
f'(x) = (x^2)/2 + 2x + C

Now solve to find the value of C.
If f'(0) = 3
3 = (0^2) + 2(0) + C
C = 3
Therefore, f'(x) = (x^2)/2 + 2x + 3

Now integrate this to obtain f(x)
f(x) = S((x^2)/2 + 2x + 3)dx
f(x) = (x^3)/6 + x^2 + 3x + C

Now solve to find the value of C
If f(0) = -1
-1 = (0^3)/6 + (0)^2 + 3(0) + C
C = -1

Therefore,
f(x) = (x^3)/6 + x^2 + 3x - 1 is your answer

PS. Puggy's answer is incorrect, that is the value of the first derivative. Forgot to do it twice.

2007-01-13 16:05:01 · answer #1 · answered by smawtadanyew 2 · 0 0

Find y=f(x) if the second derivative of f(x) =x+2 and the first derivative = 0 when x=3. Also f(0) = -1?

I appologize, but this was the only way your question made sense to me.

y" = x+2
y' = x^2/2 + 2x +c
Since 1st derivative 3 when x = 0 , we get:
0 = 3^2/2 + 2*3 + c
c = -9/2 - 6 = -21/2
so y' = x^2/2 +2x -21/2
y = f(x) = (x^3)/6 + 2x^2 -(21/2)x + k
Since f(0) = -1, we get -1 = k
So f(x) = (x^3)/6 + 2x^2 - (21/2)x -1

2007-01-14 00:26:45 · answer #2 · answered by ironduke8159 7 · 0 0

It is given that

f'(x) = x + 2

Therefore, using the reverse power rule,

f(x) = (1/2)x^2 + 2x + C

But f(0) = -1, therefore

f(0) = (1/2)(0)^2 + 2(0) + c
-1 = C

Therefore

f(x) = (1/2)x^2 + 2x - 1

(p.s. your question is not 100% clear)

2007-01-14 00:00:51 · answer #3 · answered by Puggy 7 · 0 0

Please restate your question. Make sure that you are clear in explaining what you need to do. Use proper shorthand and notation. For example, if you are saying that the value of the first derivative evaluated at 3 is equal to 0, then write f '(3) = 0.

2007-01-14 00:15:30 · answer #4 · answered by MathBioMajor 7 · 0 0

You need to resubmit this problem after you have cleaned it up. It's full of typos and crap to the point that it's not clear what you are asking for.

2007-01-14 00:32:36 · answer #5 · answered by flyfisher_20750 3 · 0 0

fedest.com, questions and answers