Recent content by recoil33

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    Understanding Vectors: Parallelogram PQRS Question

    Hey, I'll state first that I've obviously just been introduced to vectors and I have looked through the given material in class let alone watched "Khan Academy" and "Patrick JMT" video on Vectors but i can not really grasp the concepts. Question: In parallelogram PQRS let q = PQ and...
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    What is the magnitude of the resultant force and angle in this vector problem?

    Thanks everyone, I realized i was using the wrong angle, i think i confused myself with putting the force of 26N 125 degrees away in the other direction. Which should not matter, although it confused myself. Anyways, I solved it finally. As for Q2. I used the sin rule, a/SinA = b/SinB...
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    What is the magnitude of the resultant force and angle in this vector problem?

    Okay, I don't really understand vectors exactly - I think i do, but then i confuse myself. "Two forces have magnitudes of 26 N and 19 N and the angle between them is 125°. Find the magnitude of the resultant and the angle it makes with the larger of the two forces. Give answers correct to 1...
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    Max Profit & Number of Items for Maximum Profit: Find Out Now!

    That was a mistake, i must have typed it without thinking.. P'(x) = -12(n2 - 100n - 166) P'(x) = -12n2 + 1200n - 1080 P''(x) = -24n2 - 1200 When P'(0) = -12(n2 - 100n - 166) x = 10, x = 90 P''(10) = -24(10)2 - 1200 = -1440 P''(90) = -24(90)2 - 1200 = -3360
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    Optimisation Question [Cylinder]

    Q. You have been asked to design a can shaped like a right circular cylinder with height h and radius r. Given that the can must hold exactly 130 cm3, what values of h and r will minimise the total surface area (including the top and bottom faces)? Volume(Cylinder) = pi(r)2*h 130 = pi(r)2*h...
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    What Is the Exact Value of x That Minimizes y for Positive x?

    I have a function which is: y = 27x2 + 2100/x dy/dx = 54x - 2100/x2 Critical points are for what x values, is y undefined or equal to 0? Therefore, in this case i can only see the value of 0, which would cause the function to be undefined. Due to x2 being on the denominator. EDIT...
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    Max Profit & Number of Items for Maximum Profit: Find Out Now!

    P' = -12(x2 - 100x - 900) (I converted n to x because i find it easier to work with) Expand the brackets: P' = -12x2 + 100x + 900 Therefore: P'' = -24x + 100
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    Max Profit & Number of Items for Maximum Profit: Find Out Now!

    The total profit $P, generated from the production and marketing of n items of a certain product is given by: P = -10800*n-4*n3+600*n2-166 How many items should be made for maximum profit? What is the maximum profit? Firstly, I think i would find the derivitive of the function. P'...
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    How Does a Walking Person's Shadow Change Speed?

    "Differential Approximation" A person of height 1.9m is walking away from a lamp-post at 1m/s. The light on the lamp-post is 5.1m above the ground. 1. At what rate (in m/s to the nearest cm/s) is the length of the person's shadow changing? 2. At what speed (in m/s to the nearest cm/s)...
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    1. Burning butane (C4H10) produces gaseous carbon dioxide and water.

    Sorry, I didn't even read the question right -.-' It's really simple, thanks anyways. (I didn't realize that they said given 22-100 degrees, whereas i thought the change in temperature was unknown, as well as the mass.)
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    1. Burning butane (C4H10) produces gaseous carbon dioxide and water.

    1. Burning butane (C4H10) produces gaseous carbon dioxide and water. The enthalpy of combustion of butane is -2650 kJ/mole. Determine how much water you can heat from room temperature (22 Degrees) to boiling with 1 kg of butane. Therefore: 13O2 + 2C4H10 ---Heat---> 8Co2 (g) + 10H2O(l)...
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    How Does Implicit Differentiation Apply to Polynomial Equations?

    Ahh that makes sense, the source from which i got the question had a massive gap between the 6 and (x2+4)6 so i did not think to realize they were together. Yes, i know the answers were obvious, although i could not see where i was going wrong. Thank you.
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    How Does Implicit Differentiation Apply to Polynomial Equations?

    Question: y6 + 6 (x^2+4)6 = 9 6y5 .dy/dx . 6(x2 + 4)5 . (2x) = 0 6y5 .dy/dx = -6(x2+4)5 .(2x) dy/dx = 6y5 / -6(x2 + 4)5 .(2x) dy/dx = 6y5 / 12x(x2 +4)5 Although the answer is ment to have y5 as the numerator, not 6y5? ------------- Another Q. [Simplifying result from...
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    Differential equation (product/quotient)

    @ JThompson Yes, the equation was sapose to be u = (5x +2)7 u' = 7(5x+2)6 The equation will be incorrect if i accidently put u'(x)*v(x) and v'(x)*u(x) in the wrong order? @Hallsofivy Sorry, bit new to the terminology of the mathematics. I guess it's not a differential...
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    Differential equation (product/quotient)

    I have several questions, so i'll post these as i go. 1. y = (5x+2)2/((x+5)3)2 u = (5x+2)2 u' = 7(5x+3)6 . (5) v = (x+5)3 v' = (3(x+5)2).(1) Quotient = (u(x)*v'(x) - v(x)* u'(x) / v(x)2) (5x+2)7 . 3(x+5)2 - (x+5)3 . 7(5x+5)6 .(5) / ((x+5)3)2 [ If i knew how to put this under...
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