You are not logged in.
It's a joke
yep, it's a joke.
appologise, grassy homes.
Sounds like a job for Crazy Holmes
I'm a little stuck again:
find the gradiaent of the tangent and the normal to the following curves at the stated point.
y = x + 1/x at x = 1/2.
dy/dx = -x^-2 + 1 = 3/4, thus the gradient of the normal is -4/3.
I can work out most of these sums, I am doing somthing wrong with the negative power...
I'd start with x/x^2, firstly I'd "reciprocal" which basically means you take the value with the power (x^2) and move it to the top, when you do this you MUST change the sign of the power:
x / x^2 = x * x^-2
I'd then do the same with the next part of the sum, giving you b - ax * x^-3. Now all that is left is
(x * x^-2) + (b - ax * x^-3), since none of the values share similar powers, I think this is as far as you can go. (Don't take my word for it, I'm new to this too).
Thankyou, I was drunk
Won't happen again.
maybe you'll have heard of the expression "pwned" which is derived from the word "owned". I recently read a question asking how this word was to be pronounced, many people had many thories. My theory is that since it is internet slag, the word was not meant to be pronounced (only typed) and thus the internet is spawning a global language that has no pronounciation. Do any other languages such as this exist?
Maybe 6 was in a bar and heard some really bad things about 7.
x(x-1)(x+1)
do I multiply the brackets by eachother first, or each bracket by x?
Consider this: you have a bag of sweets containing 10 whole sweets but lots of shrapnel in the bottom of the bag. The shrapnel could make up 3/4 of a sweet yet you'd still say you have 10 sweets. Then in this case, are you not rounding down even though you have more than .5? I don't think you can "prove" which way to round, people just do it to simplify a number, it's not actually a mathematical theory (or somthing).
Thanks again, one final question, the only one left that I am unsure of my workings:
y = sqrt(4/x^3) = sqrt(4x^-3) = 2x^-3/2
dy/dx = -3x^-5/2
Is this right?
I think people like to round up becuase the most public use of rounding is related to money handling. rounding up = more $$$.
in a question like y = 3x^4, do you multiply the 4 by the 3 to make dy/dx = 12x^3?
i.e. y=ax^b dy/dx = (ba)x^b-1
I was subtracting 1... but from +4 and not -4
Thanks.
Hi guys and girls, long time no see. I've been away for the Christmas holidays (away from my computer at least) but now I am back to bug you with more laughably simple questions!
I've moved on to the topic of calculus and am having a little trouble with some differentiation questions. I understand how to do basic questions such as y=x^10 dy/dx = 10x^9.
I think these are also correct, only my book shows the answers in a different format, I'd be obliged if you could check.
y = 1/x = x^-1 dy/dx = -x^-2 (book says: -1/x^2)
y=sqrt x = x^1/2 dy/dx = 1/2x^-1/2 (book says: 1/ 2sqrt x)
y= -1/x^4 = -x^-4 dy/dx = 4x^-3 (book says: 4/x^5)
P.S. Happy New Year!
I'm still having a little trouble with this.
y = ax^2 + bx + c
and our answer needs to be in the format
(dx + e)(fx + g) where:
e * g = a * c
and
e + g = b
in a question like y = -x^2 + 3 + 4 I would take the negative co-efficient from x^2 and reverse the other signs, factorise and then put the - back in front of d making d * f = a??
If I have a question like y = -2x^2 - 3x + 2
I'll change it to -(2x^2 + 3x - 2)
like this I can see that e = 4, g = -1, d = 2 and f = 1.
This is where I go wrong, into my answer I would now write
-[(2x + 4)(x - 1)]
Which of cours, is wrong. Do I need to divide e by d?
The picture of yours that I see has the hat on! Are you trying to change it back to your normal one?
Merry Christmas Krassi and Mathsy
so you're saying I should divide the whole equation through by the co-efficient of x^2 and then factorise normally, multiplying the co-efficient back in at the end?
I have problems when trying to factorise a quadratic where the co-efficient of x^2 is < -1 i.e.
y = -2x^2 - 3x + 2
What are the steps I need to take to get an answer in the form (ax + b)(cx + d)?
Learning maths for the sake of learning maths is probably very dull. Most people learn maths because they need to for somthing else i.e. software development.
I've found studying maths can be a little tedious, but I only fail at learning it if I try to understand the maths from the start. When I am being taught a new method in mathematics, instead of trying to UNDERSTAND what is going on, I just accept the steps I need to take and take them. The understanding of what's happening usually sinks in when you have been working with somthing for a while.
4x - 3x = CUBE ROOT OF 1/2?
I thought I knew how to do this, but maybe not.
To solve the equation you just have to remember that whatever you do to one side you must do to the other. The idea is to get the x on it's own.
so 4x^3 - 3x = 1/2 becomes
4x^3 = 3x + 1/2
You see that I made the "-3x" on the left equal 0 by adding 3x to it. Because I added 3x on one side I must add 3x onto the other side too.
For the next step you must take that 4 off from in front of the x^3 (that 4 means multiply so you must divide 4x^3 by 4 to get it as x^3). Again, since you have divided 4 on one side, so you must on the other.
x^3 = (3x + 1/2) / 4
Finally, the opposite of "cubing" a number (which is what the ^3 does) is finding it's cube root. so x = CUBE ROOT OF (3x+1/2)/4
-2x = CUBE ROOT OF 1/8
You'll probably need a calculator for that last step
The perpendicular line would be:
y = 3/2 x + 1
2y = 3x + 2
Thanks irspow but you're a bit late