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  1. M

    Probability math help

    1. Homework Statement A new drug is in trial, and it is found that the drug will cause adverse effects on some patient. 5% will have diarrhoea and 3% develop a rash after taking the drug. Also, 7% of patient have either diarrhoea, rash or both after taking the drug. Need to find the...
  2. M

    Whats the acceleration?

    the following data apply to the speaker system: coil diameter = 5.8cm coil turns = 86 coil and cone mass = 30g magnetic flux density = 0.12T Current in the coil = 1.8A Using the above data, the acceleration of the cone will be? A) 12.6 b) 79.3 c) 113 d) 247 This comes from my revision sheet i...
  3. M

    Experiment and pu tiron nail into water

    So i did an experiment and pu tiron nail into water and serveral days later it starts to rust. and i looked at the book and the chemical process is 1)Fe loses electron 2) that electron + oxygen + water produces hydroxide 3) hydroxide and Fe ion reacts and form Fe(OH)2, green rust 4)...
  4. M

    How charged particle got to do with magnetism

    hello, I am not too sure of how charged particle got to do with magnetism. "Magnetism is a force of attraction or replusion that acts at a distance. It is due to a magnetic field, which is caused by moving electrically charged particles or is inherent in magnetic objects such as a magnet."...
  5. M

    Find the 50th derivative of the function

    1. Homework Statement Find the first, second, third, fourth, fifth derivatives of the function y = sin 3x. Find a rule that can help to find the 50th derivative of the function. It's urgent! 2. Homework Equations y= sin x y= cos x y' = cos x...
  6. M

    Polar form

    1. Homework Statement solve below using de Moivre's theorem, in polar form z^3 = i 2. Homework Equations r CIS theta Answer:CIS pi/6, CIS 5pi/6, CIS (-pi/6) 3. The Attempt at a Solution r^3 = sqrt(0^2+1^2) r^3 = sqrt (1) r = sqrt (1) no idea how to get the angle
  7. M

    Frequency and penetration depth

    why does the increase of sound frequency will decrease the penetration depth? how can this related to diffraction of sound?? Is it because they can be easily reflected?? need answer desperately, thx
  8. M

    Ultrasound machine

    how does ultrasound machine detects the reflected wave? i have read a bit of information and unfortunately Im still unsure how they detect the wave. "The rapid shape changes, or vibrations, of the crystals produce sound waves that travel outward. Conversely, when sound or pressure waves...
  9. M

    Use the chain rule to find the derivative

    1. Homework Statement f(x) = ((x^2+2)^2)/(x+2)^1/2 Use the chain rule to find the derivative 2. Homework Equations None 3. The Attempt at a Solution ((x^2+2)^2)(x+2)^-1/2 PS: Answer in the book is 3x((x^2+2)^1/2) I have no idea how they get it there, would like some help, thx!
  10. M

    Is nitrogen narcosis a type of HPNS

    :rolleyes:
  11. M

    Pure carbon and graphite have the same resistivity?

    I am just wondering if pure carbon and graphite have the same resistivity? Resistivity for pure carbon = 3.5 x 10^-3Ωm:frown:
  12. M

    Electrical resistance

    1. Homework Statement this is not a homework question... i want to know density vs resistance 2. Homework Equations R = ρl/a 3. The Attempt at a Solution none so far
  13. M

    Pascals Triangle

    how do i find the independent of x in (6x^(2)-3/x)^6 I know that the formula nCr a^(n-r) b^r i have got an answer of n = 6 and r = 4 i just wanna make sure that im correct and i would like someone to give me a hand~ :)
  14. M

    Spherical coordinate system

    I do not understand Spherical coordinate system. I'm asked to compare the differences with Cartesian coordinate but I have no idea how to start. So I would like some help that will at least give me a understanding of the spherical coordinate system, thx
  15. M

    F(x) = 1/(x+1) - 2/9

    f(x) = 1/(x+1) - 2/9 just wondering whats f-1 (y) will be ill have a go at it now thx
  16. M

    Oil in a microwave oven

    just wondering if i put oil in a microwave oven will the oil get heated and why? i know polar substances will be heated but im not sure if the same thing will happen to non-polar substance like oil
  17. M

    Converting recurring decimal to a fraction

    3.741 (41 is recurring) answer is 1852/495 but ii don't know how to work it out thanks :)
  18. M

    Projectile motion

    ummm i dont know how to calculate the distance if: horizontal- v=2, u=2,a=0, s=??? Vertical- v=???, u=0, a=9.8 s=1
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