Miembros: Melody

Guest:
suppose that the rate of inflation for the last four years was 3.9% per year. if a home costs 125,000 today, how much would it have cost four years ago?

You just use the compound interest formula

S = P(1+r) ⁿ

S is future value - which is 125,000 (Because the question is looking back, it wants you to work out an earlier value)
P is present value (or initial value) which is what you are trying to find.
r is the rate per compounding period. In this case the compounding period is in years. r = 0.039
n is the number of compounding periods which is 4

Try doing it yourself now.

Melody4 feb 2014

+118737

mathy6161:
:D What is 5x>64

simple, just divide both sides by 5

You only need to turn the sign around if
1 You multiply or divide by a negative number
2 You swap sides
3 you take the reciprocal of both sides (turn both sides upside down)

Melody4 feb 2014

+118737

student789:
cscx/cotx+tanx=cosx

Hi Student789

co sec = 1/ sin

co t = 1/ tan

** The first letter of the most familiar ratio matches the 3'rd letter of the less used ratio,

Lets see,

1/sinx divided by 1/tanx + tanx = cosx

1/sinx multiplied by tanx + tanx = cosx

NOW, tanx =sinx/cosx

1/sinx times sinx/cosx + sinx/cosx = cosx

1/cosx + sinx/cosx = cosx

(1+sinx) / cosx = cosx

1+sinx = cos ²x

1+sinx = 1-sin ²x

sin ²x + sinx = 0

sinx(sinx + 1) = 0

sinx = 0 or sinx = -1

Can you finish it ?

Melody4 feb 2014

+118737

Guest:
how do multiply negatives

If you just want to multiply negative (and positive) numbers its is simple and it works exactly the same for division as well.

If the signs are the same the answer is positive.
If the signs are different the answer is negative.

It's adding and subtracting that is more complicated.

Melody4 feb 2014

+118737

SelinaMarie:
-7* (natural logarithm) ln(2x)=4
could someone show me how to work this out?

Hi SelinaMarie

It is nice to see you again.
I know that you answer questions as well as ask them and I really appreciate this.
I do an end of day wrap each night. If you read it already, that's great, if not maybe you would like to sometimes.
I know you are not a member yet and I would really like you to join up.
I've given a list of benefits in one of my recent nightly wraps if you would like to take a look.

Now to your question,
-7* (natural logarithm) ln(2x)=4

-7ln(2x) = 4

ln(2x) = -4/7

e ^ln(2x) = e ^-4/7

2x = e ^-4/7 Edit: Sorry, I like Serena was right, i did drop an e. sorry

etc

I got the exponents up in the air by using the 'sup' button that is located above the icons.

e and ln cancel each other out, much like + and -
so

e ^ln6 = 6

10 ^log4 = 4

ln e ⁷ = 7lne = 7*1 = 7

log 10 ¹² = 12log10 = 12*1 = 12 ( base 10 of course)

Any questions? Just ask.

Melody4 feb 2014

+118737

chrism241953:
define x-1

Sorry, you'll have to explain what you mean first.

Melody4 feb 2014

+118737

Guest:
-15+n=-9

Just add 15 to both sides

Melody4 feb 2014

+118737

bump

Melody4 feb 2014

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