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+3146

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[input]simplify(sqrt(2)/2)[/input]

adminOct 13, 2013

+118725

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Find the slope of (m) of AB for the following points: A (5,3), B (-2,1)
Sammy's formula is correct but he has substituted in the wrong values,
gradent(slope) = y(#2)-y(#1) / x(#2)-x(#1)

x ₁=5, y ₁=3,
x ₂=-2 y ₂=1

gradient = [y ₂ - y ₁] / [x ₂ - x ₁]
gradient = (1-3) / (-2-5) = -2 / -7 = 2/7

MelodyOct 13, 2013

+118725

0

I have never owned or used a calculator that does any of those things.
The calculator on this site does have those functions but I haven't tried to use them.
If you use lots of decimal places in your working and only round at the very end you should not get many rounding discrepancies.

MelodyOct 13, 2013

+33

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Thankyou kindly! I'll be sure to post more interesting trig questions as they emerge, but so far, when doing my math i come up short by 4 when the answer was in the 1000's, i think it's the rounding of the calculator on here, since i lack one that can do sec, csc, cot and their arc functions.

dndlockeOct 13, 2013

+118725

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That is ok, you will remember it now. Glad I could help.

MelodyOct 13, 2013

+33

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Oh, it's that one rule thingy where you can't have squareroot on the bottom of a fraction. aighty, wasn't sure, but i vaguely recall that being mentioned years ago, it is of course not present in the book so far as i see.

dndlockeOct 13, 2013

+118725

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I am sorry, you were right but so was your book.

1/root2 = (1*root2)/(root2*root2) = root2/2

The author has rationalized the denominator (made the fraction so that the bottom is rational)

It is considered to be simplified if the demoninator is rational.

MelodyOct 13, 2013

+118725

0

3x+8=5x-20=5x+4y

Use 3x+8=5x-20 to get the value of x
substitute in x to get the value of y.

I hope this will be enough help.

MelodyOct 13, 2013

+118725

0

2*10^3+1.9*10^2

dndlocke is correct but the answer he/she got is not finished because it is not in scientific notation.
21.9*10 ²

= 2.19*10*10 ²

= 2.19*10 ³

You also could have done it on your calculator
2 exp 3 + 1.9 exp 2 =
The answer is 2190
But then you have to change it to scientific notation by yourself, I've never owned a calculator that will do that for you.
the exp button on your calc may look like 10 ^x

MelodyOct 13, 2013

+33

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I actually ran into this same thing later on in the book, it was giving the 6 ratios for a right triangle with 45 corners, the sides are 1, 1, and sqrt(2) once more they state sin is sqrt(2)/2 and cos is sqrt(2)/2 This shouldn't be the case, yet it printed it like that again, in a completely different chapter. I'm trying to reason why they did this the way they did, for instance if they are wrong, how did they reach that conclusion?

dndlockeOct 13, 2013

+118725

0

the answer in the book is wrong.
You are correct.

MelodyOct 13, 2013

+118725

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Mujib has factorised correctly. Mujib and I both assumed that you were asked to factorise, maybe you were asked to graph? Thinking about it that is probably moe likely but you have to start the same way anyway.

Your problem was

y=x ²+2x-15
so
y= ²+2x-15

To factorise you need to look for 2 numbers
that multiply together to give -15
and add together to give 2
(3 and 5 might be worth looking at)

Since they multiply to give a negative number, one is pos and the other neg
Since they add to a positive, the bigger number is the positive one.
so, 5 and -3 work
hence
y=(x+3)(x-2)

MelodyOct 13, 2013

+118725

0

If you just wanted
sin(a negative angle) Mujib is right.

sin(-theta) = -sin(theta)

I don't think that this is what you were asking.

MelodyOct 13, 2013

+118725

0

Just in case you have already seen my answer, I did fix a little typo in the first line of the solution.

MelodyOct 13, 2013

+118725

0

Okay, I still don't understand, maybe you are studying maths that I have not done or maybe the meaning just gets lost in the translation.
I have not heard the term potencial equation before, do you just mean an equation that is not exponential? (no powers)

Your original question was
how trasform I(z)=I(0)*e^ln(1/10)*z in a potencial equation?
I am going to assume l is a function.

I(z)=I(0) * e ^ln(1/10) * z

I(z)=I(0) * (1/10) * z

I(z)=I(0) * z * (1/10)

I(z)=I(0) * z / 10
-------------------------------

l(0) = l(0) * 0/10 = 0
so
I(z)=I(0) * z / 10 = 0*z/10 = 0

So, with my limited understanding of your problem I get an answer of 0

MelodyOct 13, 2013

Oct 12, 2013

0

eight less than three quarters of a number is 91. find the number
let x=the number
eight less means minus eight
three quarters of a number is (3/4)x
so --> (3/4)x - 8 = 91
and solve normally
add eight to both sides
so (3/4)x = 99
multiply by the reciprocal of 3/4
x = 132

GuestOct 12, 2013

+33

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It rolls down stairs alone or in pairs, rolls over your neighbor's dog. It's great for a snack and fits on your back. It's Log, Log, Log!

Or log is the basic question "How many of one number do we multiply to get another number?"

dndlockeOct 12, 2013

+33

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To add the scientific notations together, you would get them into the same power, so in this case, change 2*10^3 to 20*10^2 then add it to 1.9*10^2. To add them, you keep the power the same, just modify the numbers themselves, so it would become 21.9*10^2
Same goes for subtraction, just the opposite of adding them.

dndlockeOct 12, 2013

0

Figured it out. -117

GuestOct 12, 2013

0

GuestOct 12, 2013

0

math sucks:
Mr. Piper's plumbing needed repairs. The plumber charged $98 for repairs and $45 per hour for labor. If the bill totaled $458 how many hours of labor were required?

GuestOct 12, 2013

+2

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Mujib AFGOct 12, 2013

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Hi you should see sin of your number then by putting negative mark you can solve your problem like this :
Sin-90=sin 90=1
Sin -90=-(1)=-1

GuestOct 12, 2013

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okey in the maths question I have:

I(z) = I(0) * e^(-a*z)

I found, a that in the first paragraph says that at Z = 1 the equation is 10%, but later said me that I have to transform this exponential equation to a potential equation.

GuestOct 12, 2013

+118725

0

I am sorry I don't understand your question.

how trasform I(z)=I(0)*e^ln(1/10)*z in a potencial equation??

x(z)?
I(0)?

e ^ln(1/10) = 1/10
e and log _e cancel each other out but that is all I can help with. I don't understand the rest of your question.

MelodyOct 12, 2013

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