Melody

Question 3

Thanks guest,

I just want to have a quick look too.

For what value of c will the circle with equation x^2 + 8x + y^2 + 4y + c = 0 have a radius of length 7?

\( x^2 + 8x + y^2 + 4y + c = 0\\ x^2 + 8x + y^2 + 4y = -c\\ x^2 + 8x +16+ y^2 + 4y +4 = -c+16+4\\ (x+4)^2+(y+2)^2=20-c\\~\\ 20-c=49\\ 20-49=c\\ c=-29 \)

That is what I get   

Firstly there is no x in the question.   Use the pronumerals that you are given.

I asked you for    \(g=? \qquad v_0=? \qquad h_0=?\)

You have not given them to me. But you have obviously done it.

what you have done is not exactly wrong.

Can you please present it properly though, as an equation, and with the correct letters. Then I will look at it with you.

There probably is some simple rule but I don't know it.

I just looked at x=1 mod 7, found a list of values, and looked for the first one that made the first two equations true as well.

Then I found the mod105  of that number.

It didn't take all that long for find the answer.

hi Finace,

First you need to determine the value of the constants

\(g=? \qquad v_0=? \qquad h_0=? \)

then substitute the values into the formula and simplify it.

now you have height as a concave down parabola function in terms of time.

Now factorize the quadratic and sketch the parabola.

See how much of it you can do by yourself? 

Get back to us with your contribution.

A request to other answerers:

This is a teaching answer please do not override it.

I'd convert them both to base 10, do the multiplication and then convert back.

k stand for kilo which means 1000 times bigger.

So

6.2kN = 6.2 thousand Newtons = 6.2*1000 =  6200 N

Same for Km

Turn all of those numbers into decimals (with a calculator). And tell us what the question becomes.

What is the remainder when the base-50  integer 12345 base50   is divided by 48base10? Write your answer in base 10.

It is simply

\(12345_{50}=(5+4*50+3*50^2+2*50^3+1*50^4) _{10}\\~\\ 5+4*50+3*50^2+2*50^3+1*50^4 \quad\mod{48}\\ =5+4*(-2)+3*(-2)^2+2*(-2)^3+1(-2)^4 \quad\mod{48}\\ =5-8+12-16+16 \quad\mod{48}\\ =9 \quad\mod{48}\\ \)

The remainder will be 9