Base Definition and 586 Threads

  1. S

    Prove this inequality using induction

    Been stuck on this one for a while now. Base case is easy, n=1, we have x <=1/3, so trivially 1-x>= 2/3 and we are done. The issue is with the inductive step, I don't know how to use the hint, infact I am struggling to understand what is meant by the hint. Any help (or a full solution) would...
  2. RChristenk

    Converting number base of decimals

    Transforming ##0.7_8## to base ##5## by multiplying ##5##: ## \begin{array}{r} 0.7 \\ 5 \\ \hline 4.3 \\ 5 \\ \hline 1.7 \\ \end{array} ## ##0.7_8={0.\dot{4}\dot{1}}_5##. This is the correct answer. Transforming ##0.12211_3## to base ##9## by multiplying ##9##: ## \begin{array}{c}...
  3. RChristenk

    What is ##7 \times 7## in base ##7##?

    In base ##7##, only the digits ##0,1,2,3,4,5,6## can be used. So ##7 \times 7 = 49## in base ##10##, but ##49## is a multiple of ##7## seven times, so at the right-most digit position of the answer, I can put down a ##0## and carry a ##7 ## to the next-left digit position. I can't put down ##7##...
  4. S

    Chemistry How do I know whether a base is strong or not?

    So I know that I can get whether an acid is strong or not from a table where if ##pK_a## < 0 than it is a strong acid, but there is no such table for bases, so how do I determine whether a base is strong or weak? Also.. for metalhydroxides MOH, which will be strong and which are weak bases...
  5. A

    I Why is length considered a fundamental (base) quantity?

    Hello all, Textbooks define fundamental or base quantities as those quantities which are not expressed in terms of other quantities and they define derived quantities as those quantities which are expressed in terms of other quantities. I have the basic understanding that the choice of a set of...
  6. A

    How can vinegar attenuate the pain of a bee sting? (acid base reaction)

    Hello, I have been working on this subject but I am not sure how to deal with it. I am looking to prove how can vinegar attenuate the pain of a bee sting. I have chosen a specific vinegar that is of 6° and 50 ml and Know the molecular weight of acetic acid is 60g/mol. The bee sting contains...
  7. samy4408

    Something that doesn't make sense to me about calculating the pH

    Hello , the problem that i refer to is present when we try to calculate the pH of a solution without any assumption. in a lecture entitled "calculating the pH of a strong acid/base solution " after adding a certain amount of HCl in water we are asked to calculate the pH (the amount of HCl and...
  8. E

    What is the Effect of Floating MOSFET Base Plate?

    My specific system will benefit from having the MOSFET base plate floating. Are there any downsides to leaving a MOSFET base plate floating? Are there any reasons not to?
  9. S

    Volume of solid having triangle base and semicircle slice

    First, I tried to find the equation of line passing through (2, 0) and (0, 3) and I got ##y=3-\frac{3}{2}x## Then I set up equation for the area of one slice, ##A(x)## $$A(x)=\frac{1}{2} \pi r^2$$ $$=\frac{1}{2} \pi \left( \frac{1}{2}y\right)^2$$ $$=\frac{1}{2} \pi...
  10. FEAnalyst

    Heat sink - calculating temperature at the base

    Hi, I've checked the literature but couldn't find any formulas or examples for this particular problem involving heat sink with straight fins: As you can see, I want to assume: - power at the bottom surface - convection (known ambient temperature and heat transfer coefficient) at the...
  11. chwala

    Find the time taken to travel from top of slope to base - Mechanics

    Now this is a textbook example with solution. I understand working to solution...my only reservation is on how they used acceleration. The cyclist, i understand was traveling at a constant acceleration of ##2## ##m/s^2## before reaching the top part of the slope. Now, if he is descending...
  12. S

    I Base Motion and Vertical Beam - Basic Reaction Forces?

    So I am trying to understand how to estimate the amount of deflection [D] the vertical beam shown above would experience if the base it is attached to is accelerating at a constant acceleration [a] of 9.81 m/s. I assume the Force [F] would be equal to weight of the vertical beam (mass x...
  13. M

    MHB Representation of signed integers of base B

    Hey! :giggle: Consider a representation of signed integers of base $B$, in which the digits are listed in descending order of importance, with the least significant digit corresponding to a positive, and the next digits to an alternate negative and positive value. Thus, a number of this...
  14. rifal

    How do I fix the error connecting Snort and BASE databases?

    I installed snort and I want to connect the database with BASE but an error occurs, I don't know where I went wrong, everything is running smoothly but not with BASE connection with the database I suspect if I'm wrong when running the command: # sudo mysql_secure_installation what should i do...
  15. Mayhem

    Chemistry Choosing an appropriate base for deprotonation

    Normally you would deprotonate a ketone alpha carbon with a strong base like KOH or LDA, but in compounds where ester functional groups are also present, this would cause annoying side reactions. Since the pKb of acetate (around 9.25) isn't much lower than the pKa of an alpha carbon (let's say...
  16. I

    Chemistry PKb of weak base titrated with strong acid

    What is true about the pK of the analyte? a) pKa = 9.2 b) pKb = 9.2 c) pKb = 4.8 d) pKa = 11.7 The halfway point is at point 4, at approximately pH=9.2. Therefore, the pOH = pKb = 4.8, and I think the answer is c). The solution says b) is the correct answer. Could anyone explain why, or whether...
  17. H

    Biology Is Pol I Necessary for Base Excision Repair?

    I think (C) should be one of the answers too. I think that base-excision repair does not need the 5' to 3' exonuclease activity of Pol I, either. Am I right?
  18. M

    Transistor base voltage calculation

    Hello, I am trying to find base voltage. In attached picture (using Multisim) there are two separate circuits. Here is how I am doing the voltage divider: Circuit on right: Vb = (Vcc - .7)*R6/(R6 + R5) = 3.2V which matches Multisim result. No problem here. Circuit on left: Vb = (Vcc -...
  19. Y

    Question on base class access spec. and constructor

    I studied about 20 pages, I understand the base class access specification as shown; My question is why is it necessary to have private and protected base class access specification? If z is public in Base class, other programs can access z directly regardless the Derived class say it's private...
  20. V

    Do leaves really always have an axillary bud at the base?

    Would love some insight: We're always taught that you can tell a leaf by the axillary bud where the petiole connects to the stem. But what if the axillary bud has developed into a stem/branch? Would it be correct to say that leaves often lack axillary buds at their junction with the stem (maybe...
  21. A

    I Base Pi Integers: Isomorphism with Rationals?

    A proper number is expressed in \pi in a similar way as a decimal integer is expressed in base 2. For example, 4375_{\pi} = 4{\pi^3}+3{\pi^2}+7{\pi}+5. The only exception I make is that the 10 digits are included when expressing a number with \pi. To clarify, the first positive such numbers are...
  22. Purplepixie

    MHB Using moments to calculate weight of Pyrometer stand base

    I am trying to design a free standing stand for a pyrometer, which weighs 750g. The pyrometer needs to be 1.5 metres above ground level. The stand will be constructed entirely in steel. The layout of the stand is shown in the uploaded diagram Pyro_stand.gif. How can I derive expressions for the...
  23. P

    Comp Sci Convert between base system in C on Linux

    We have been requested to run this on linux. I am able to read in the original base system and then I am able to enter the number. As soon as I enter the original number the system reads out "Enter the base of the output:" then does not allow the user to enter the second base. Instead it just...
  24. Maverickans

    Impedance calculation from base values

    Hello, I'm reading a paper at the moment and I came across this: We now apply the solution technique to a single-phase, 3 kW, 240 V ASD heat pump. The ASD has smoothing capacitor C = 4200 pF, (corresponding to approximately 6% ripple in dc voltage), and total impedance (sum of Thevenin and...
  25. K

    Curvilinear coordinate system: Determine the standardized base vectors

    How I would have guessed you were supposed to solve it: What you are supposed to do is just take the gradients of all the u:s and divide by the absolute value of the gradient? But what formula is that why is the way I did not the correct way to do it? Thanks in advance!
  26. G

    The velocity of the center of the base of a rolling cone

    Let the vertex of the cone be ##O##, the contact point on the cone all the way to the right be ##D## touching ground. Then ##v_{\text{D relative to the table}} = v_{D/table} =0## since it rolls without slipping. Due to relative motion $$\vec v_{P/table} = \vec v_{P/D} + \vec v_{D/table} = \vec...
  27. J

    Understanding the base emitter voltage in a common emitter NPN BJT

    ##V_{BE}## is basically the difference in voltage between the base terminal and the emitter terminal. Normally when silicon is used and the transistor is biased to operate in the active region, ##V_{BE}## = 0.7 V approximately. The way I understand this is that for an npn BJT, the applied...
  28. Luke_Mtt

    I Calculate a spin state as a function of the base spin states

    Practically it is said that, given two spin states |u⟩ (up) and |d⟩ (down) - which are the spin measured along the +z and -z semiaxes - such that they are orthogonal ( ⟨u|d⟩ = ⟨d|u⟩ = 0), it is possible to write any other spin states using a linear combination of these two (because they are a...
  29. F

    B Push from a Narrow Base vs Wide Base

    Hello! When moving an object, how do you describe the changes when you push from a narrow base vs a wide base? For example, say you push something heavy with your palm vs your index finger. It feels easier to push from a palm rather than a finger even if the force from my arm is the same but...
  30. G

    Chemistry What causes the release of ammonia in organic compounds?

    I don't really have any idea how to approach this, but the answer says that it is the compounds which are more basic than ammonia liberate it.
  31. T

    A Simple question on the derivative of base frame

    I apologize: despite my verbosity, this is, I hope, a simple question.) Consider the following relationship between a rotating reference frame and an inertial reference frame (both Bold), through a rotation matrix: (the superscript is to designate the rotating frame e(1) and the I is for the...
  32. E

    B Is "ten" independent of the chosen number base?

    This topic is quite confusing. For instance, if I write ##14_6##, do I pronounce this as "ten", even though we'd probably just say "one-four, base six"? That is to say that we'd treat "ten" as a number of things that we could count out (i.e. corresponding to a certain number of sticks). Another...
  33. V

    Modeling a wingsuit base jumper's speed

    Fgravity = m*g Ffriction = k*A*v^2 Ftotal = Fgravity - Ffriction a = Ftotal/m v = v+a*dt if t<7 then Fgravity>Ffriction if 7<t<67 then v =55,88 (meters per second) if t>67 then A = 45 (square meter) if t>67 then Fgravity<Ffriction the t defines the seconds the first 7 seconds are the free fall...
  34. M

    A Irradition to base of cylindric gray gas volume

    Anyone who has an idea for how to calculate the irradition [W/m2] to the base of a cylinder with radius R, height H, absorption coefficient k, and temperature T? I've looked at the approach with mean beam length by Hottel but cannot figure out what to do when it is the base of the cylinder that...
  35. Mr-Thirty

    Concentrations at equilibrium (strong base weak acid)

    So my professor covered acids and bases recently, and this is how he presented the method (please see attached word document). I believe its the same as the I.C.E method, though I am not sure. Anyways my problem is perhaps conceptual, but I don't understand why the concentrations at equilibrium...
  36. karush

    MHB Adding in Base 20: 1HE1C +JDF0 = 2H7GC

    Add in base 20 1HE1C +JDF0= 2H7GC from calculator By hand I couldn't get the H Using 1 2 3 4 5 6 7 8 9 A=10 B=11 C=12 D=13 E=14 F=15 G=16 H=17 I=18 J=19 K=20
  37. mastermechanic

    Why weld joints are stronger than the base material itself?

    I wonder it for a long time and still couldn't find a reliable source. I've seen some posts on the internet saying that welds are mostly stronger than the base material but at first glance it contradicts with my intuition. I'm working on a bicycle frame for myself and the welds are important for...
  38. S

    I Is it possible for a non-natural number to be a number base?

    A commenter at Quora said that is possible for there be something like 12π which would evidently be ( π + 2 ). This seems ridiculous. https://www.quora.com/What-mathematical-symbol-is-the-hardest-to-explain-to-non-mathematicians/answer/Peter-James-Thomas
  39. Terrycho

    (Bipolar Junction Transistor) The Current Gain of Common Base Amplifier

    Everything is okay besides the current gain of this circuit, which is "g" there The formula of current gain is I_out/I_in If I call the current flows to R_e I_2, according to KCL, the following formula must be satisfied. I_in + (β+1)I_b = I_2 Therefore, to know I_in, we should use the...
  40. K

    What is the equation for calculating [H3O+] in a salt of weak acid and base?

    Because of character limit I have exposed my question in the attached pdf
  41. Benjamin_harsh

    What is the total moment of inertia using the negative area method?

    ##I_{total} = (I_{1} + A_{1}d_{1}^{2} ) + (I_{2} + A_{2}d_{2}^{2}) + (I_{3} + A_{3}d_{3}^{2})##(d is the distance between centroid of the individual box and centroid of whole shape.) By negative area method by joining the gaps in I section. ##I_{total} = (I_{1} + A_{1}d_{1}^{2} ) - (I_{2} +...
  42. C

    Safe zero base reactivity level nuclear fission reactor?

    There are already 4 generations of nuclear fission reactors. (Compare https://en.wikipedia.org/wiki/Nuclear_reactor#By_generation.) However among these, there does not seem to be a (maximum) safe nuclear fission reactor design, which immediately stops the nuclear chain reaction when the reactor...
  43. Z

    What is the optimal communication time for a given set of parameters?

    Hi, I am trying to solve the following equation: ##\mathbf (t_s + t_wm)log(p)+ 2t_h (\sqrt{p} - 1) ## ##\mathbf (10+0.01 * 1000) log(36) + 2 * 2(5) ## I think log(36) would be 18. Note log is ##\mathbf log_2 ## Somebody please guide me. Zulfi.
  44. M

    Forces acting on the base of a crane

    I am attempting the work out the forces acting on the base of a crane. I am yet to come across forces at the base of a crane and am confused as to how to work out the reactionary/moment forces. Any help would be greatly appreciated.
  45. trurle

    Pidgeon process for the Moon base ISRU?

    I am evaluating the possibility what magnesium may be the most-easily obtainable structural material on Moon. The following ISRU sequence is proposed: 1) Regolith melt electrolysis produce ingots made of ferro-silicon, as by-product of breathable oxygen production 2) Ferro-silicon ingots are...
  46. R

    Exponential function with negative base

    Homework Statement -2^x = y Homework EquationsThe Attempt at a Solution When I plug this function in my graphing calculator, it appears to be 2^x reflected across the x axis. This doesn't make sense to me. For example, for x values of 1 and 2, the value of y is not on the same half of the...
  47. Y

    MHB Limit with x in both base and exponenet

    Dear all, I am trying to solve the following limit: \[\lim_{x\rightarrow 0}(e^{ax}+x)^{\frac{1}{x}}\] where \[a\] is a constant. I know that the limit is equal to \[e^{a+1}\] but not sure how to prove it. Thank you.
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