I have limited number of friends.

I am basically a loner.

]]>mathland wrote:ganesh wrote:I wan in the habit of smoking and alcohol. For close to 20 years. Fortunately, from 2010, I am a teetotaler. And strictly no tobacco from 2010. I feel much better. My health is improving.

Bad habits are hard to break but doable. In my case, it is an ugly sin that has me crippled for years. I pray for God to restore me to my former walk with Christ.

Do able, yes, but takes a lot of determination. And courage.

You don't know my background. I am a Christian by faith & persuasion. I came to Christ long ago. There should be a change in my life that stands out, a change that the secular world cannot understand. If surrendering to Jesus is not enough to change a person from a life of sin to a life of holiness, then the Bible becomes just another book of stories.

]]>Because 36 is also triangular, 666 is a doubly triangular number. Also, 36 = 15 + 21; 15 and 21 are also triangular numbers, and 15² + 21² = 225 + 441 = 666.

The Roman numeral for 666, DCLXVI, has exactly one occurrence of all symbols whose value is less than 1000 in decreasing order (D = 500, C = 100, L = 50, X = 10, V = 5, I = 1).

]]>A roofing contractor purchases a shingle delivery truck with a shingle

elevator for $42,000. The vehicle requires an average expenditure of $9.50 per hour for fuel and maintenance, and the operator is paid $11.50 per hour.(a) Write a linear equation giving the total cost C of operating this equipment for t hours. (Include the purchase cost of the equipment.)

I must add 9.50 + 11.50 to get 21

I then multiply 21 times t.

I finally add 21t to 42,000.

My equation is C(t) = 42,000 + 21t.

Is this correct?

(b) Assuming that customers are charged $45 per hour of machine use, write an equation for the revenue R

obtained from t hours of use.I know the revenue formula is

Revenue = Quantity × Price.I say the formula is R = 45t.

Is this right?

(c) Use the formula for profit P = R − C to write an equation for the profit obtained from t hours of use.

If R = 45t, and C = 42,000, I say the equation needed is P = 45t - 42,000.

Is this right?

(d) Use the result of part (c) to find the break-even point—that is, the number of hours this equipment

must be used to yield a profit of 0 dollars.I am not too sure about part (d). What is break-even in the business world?

Thanks.

(a) You betcha.

(b) Yup.

(c) Well, there might be a typo here. R = 45t and C = (21t + 42000). So R - C = 24t - 42,000.

(d) Find the number of hours(t) that it takes for revenue to meet costs; i.e, when does R - C = 0?

]]>Mathegocart wrote:mathland wrote:Ok. I will play with this later on.

I recommend the site "postimage" instead. Less of nouveau-web math and clutter, and it loads faster.

After signing up with postimage, what is the next step?

Again, it is not necessary to sign up for postimage if you just want to post a picture.

Click "choose image" here:

After submitting an image, you will be led to a page containg links of the image.

Then copy and paste the "Direct Link" URL here:

[img]DIRECTLINK[/img]

You say?

]]>brain is 970 grams at age 1 and 1270 grams at age 3.

(Source: American Neurological Association)

Assuming that the relationship between brain

weight y and age t is linear, write a linear model for

the data.

I think the point needed is (age, weight).

If so, our two points are (1, 970) & (3, 1270).

m = (1270 - 970)/(3 - 1)

m = 300/2

m = 150

Now use the point-slope formula.

y - 970 = 150(x - 1)

y - 970 = 150x - 150

y = 150x - 150 + 970

y = 150x + 820

Correct?

]]>pizza oven for $875. After 5 years, the oven will have

to be discarded and replaced. Write a linear equation

giving the value V of the equipment during the 5 years

it will be in use.

2. Write a linear equation that expresses the relationship between the temperature in degrees Celsius C and degrees Fahrenheit F. Use

the fact that water freezes at 0°C (32°F) and boils at

100°C (212°F).

Question 1

Let t = years

V = 875 + 5t

Correct?

Question 2

I am thinking of the point (Celsius, Fahrenheit).

If so, this yields the following two points:

(0°C, 32°F) & (100°C, 212°F) = (0, 32) & (100, 212).

m = (212 - 32)/(100 - 0)

m = 180/100

I now use the point-slope formula.

y - y_1 = m(x - x_1)

y - 0 = (180/100)(x - 100)

y = (180/100)(x - 180)

Is this correct?

]]>First is correct.

second: The drop in value is 24000 - 2000 over ten years, so divide that by 10 to get the rate of decrease, is the negative m value. You have an intercept (24000) so the equation follows from that.

B

m = (24,000 - 2,000)/10

m = 2,200

I think the point we need is (year, sales).

I understand this to be (10, 24,000).

I now use the point-slope formula.

y - y_1 = m(x - x_1)

y - 24,000 = 2,200(x - 10)

Is this correct so far?

]]>For a vertical line, m = undefined.

Why is this the case?

For a horizontal line, m = 0.

Why is this the case?

Back in my school days, we were told to simply

memorize this fact of m. Most textbooks do not give a clear reason

for an undefined and zero slope.

Yes and yes.

Ok. Very good.

]]>mathland wrote:zetafunc wrote:You can calculate what each of those four terms are.

Sorry but I was not able to figure it out. Boy, do I miss yahoo answers.

Just take the derivative of each of those functions - it's the chain rule, expressed graphically.

I will play with this some more. If necessary, I will return here to continue the discussion.

]]>