Derivatives problems

[conp]

1. The price in dollars of a house during a period of mild inflation is in P(t)=(120,000)e^0.05t, where t is the number of years after 1990.
b) How many years will it be before the house is increasing in value at a rate of $11,000 per year?

2. s=4t(cos^2)t
I have
(4)(cost)^2 + (4t)(2)(-sint)
(4cost)^2 + (8t)(-sint)

Not sure if that is right when simplified

3.y=sin(x^3+7)

4.Y=5+sint/5-cost

 

[tkhunny]

No good. Missing a cosine on the right.

 

[conp]

Hey thanks for the reply I figured out the other problems but still cant get this problem. I answered the first part but cant get the second

7. The price in dollars of a house during a period of mild inflation is described by the formula P(t)=(120,000)e^0.05t, where t is in the number of years after 1990.
a. What is the derivative of p(t)?
Answer: P'(t)=6,000e^0.05t

b. How many years will it be before the house is increasing in value at a rate of $11,000 per year?

 

[Deleted member 4993]

Hey thanks for the reply I figured out the other problems

Somebodyelse answered for you!!!

http://answers.yahoo.com/question/index ... 941AA5FmP5

but still cant get this problem. I answered the first part but cant get the second

7. The price in dollars of a house during a period of mild inflation is described by the formula P(t)=(120,000)e^0.05t, where t is in the number of years after 1990.
a. What is the derivative of p(t)?
Answer: P'(t)=6,000e^0.05t

What is the derivative of

f(x) = A * e[sup:1wjkwni5]B*x[/sup:1wjkwni5]

Use chain rule

b. How many years will it be before the house is increasing in value at a rate of $11,000 per year?

11000 = 6,000e [sup:1wjkwni5]0.05t[/sup:1wjkwni5]

solve for 't' by taking 'ln' of both sides.

Please share your work with us, indicating exactly where you are stuck - so that we may know where to begin to help you.

 

[conp]

http://answers.yahoo.com/question/index ... 941AA5FmP5[/url][/color]

but still cant get this problem. I answered the first part but cant get the second

7. The price in dollars of a house during a period of mild inflation is described by the formula P(t)=(120,000)e^0.05t, where t is in the number of years after 1990.
a. What is the derivative of p(t)?
Answer: P'(t)=6,000e^0.05t

What is the derivative of

f(x) = A * e[sup:2u0tagrv]B*x[/sup:2u0tagrv]

Use chain rule

b. How many years will it be before the house is increasing in value at a rate of $11,000 per year?

11000 = 6,000e [sup:2u0tagrv]0.05t[/sup:2u0tagrv]

solve for 't' by taking 'ln' of both sides.

Please share your work with us, indicating exactly where you are stuck - so that we may know where to begin to help you.

[/quote:2u0tagrv]

Thanks I figured it out. I got 12.1 years

 

[Deleted member 4993]

How many years will it be before the house is increasing in value at a rate of $11,000 per year?

11000 = 6,000e [sup:195fwafn]0.05t[/sup:195fwafn]

solve for 't' by taking 'ln' of both sides.


Thanks I figured it out. I got 12.1 years

Correct