What is Sin: Definition and 451 Discussions

In a religious context, sin is a transgression against divine law. Each culture has its own interpretation of what it means to commit a sin. While sins are generally considered actions, any thought, word, or act considered immoral, selfish, shameful, harmful, or alienating might be termed "sinful".

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  1. R

    Convergence of Sin: Does it Approach 1 or 1/2?

    Determine whether this converges. If so, what number? http://texify.com/img/\LARGE\!\Sigma[/URL] _{0}^{ \infty } \sin^n (\frac{ \pi }{4} %2B n \pi).gif[/PLAIN] When I start plugging in values, I get : n= 0 f(n)=1 n=1 f(n)= -\sqrt{2}/2 n=2 f(n)= \sqrt{2}/2 Using the...
  2. I

    How do I show sin 1 + sin 2 + sin 3 + diverges?

    Homework Statement I was given the series sin 1 + sin 2 + sin 3 + sin 4 + ... and I must show that it diverges. Can anyone point me in the right direction as to how to go about doing this? Homework Equations The Attempt at a Solution
  3. J

    Why don't sin and arcsin cancel?

    Homework Statement This isn't really a problem, just a question... If you had sin(x) / sin^2(x), you are left with 1/sin(x), right? So how come when you have sin(x)*arcsin(x) you aren't left with 1? Isn't arcsin(x) the same as writing sin^-1 (x)? Therefore writing sin(x)arcsin(x)...
  4. W

    Proving (csc x + cot x)/(tan x + sin x)=cot x*csc x with SOHCAHTOA

    Homework Statement I am supposed to show that this statement holds true (csc x + cot x) / (tan x + sin x) = cot x * csc x using sohcahtoa Homework Equations The Attempt at a Solution I have tried this (( h/o ) + (a/o ) / ( o/a + o/h)) 1st (( ah / o sqrd )) + ((ah / o...
  5. P

    Implicit Differentiation with Sin

    Homework Statement Homework Equations The Attempt at a Solution
  6. N

    Solving an equation involving sin and cos terms

    Hi I was wondering if there is a non-numericla way to solve the following equation: 144 - 90sin x - 155.8cos x = 0 Thanks
  7. T

    Calculating Sin of Angle Between Two Vectors in 3D Space

    For two arbitrary vectors in 3D space, subtending an angle, \gamma , I know the cos relationship, but what's the sin relationship ? I ask because there is an ambiguity by only knowing the cosine form, since vector A can be either above or below vector B. cos\gamma = cos\theta_1...
  8. T

    Finding the Sin of an Angle Between Two Vectors

    For two arbitrary vectors, subtending an angle, \gamma , I know the cos relationship, but what's the sin relationship ? I ask because there is an ambiguity by only knowing the cosine form, since vector A can be either above or below vector B. cos\gamma = cos\theta_1 cos\theta_2 + sin\theta_1...
  9. J

    Stuck on this integral (cos and sin)

    Homework Statement Integrate (sin5x)(cos4x)dx Homework Equations The Attempt at a Solution I tried substituting u as (sin5x), but wound up with something way more complicated than what I started with. Same thing happens if I substitute cos^4 for u. I have no idea what to try...
  10. X

    Is Using Exponent Identities Allowed in Solving Trigonometric Integrals?

    Homework Statement Compute \int^{\pi/2}_{0} \frac{sin^{2009}x}{sin^{2009}x + cos^{2009}x} I used the identity cos^{2}= 1 - sin^{2}, but instead I set the exponent as 2009. And so I ended up with the answer being -1. I'm just wondering whether this is a legal solution or am I not allowed to...
  11. T

    How can i tell a period of a function involving sin and cos

    Homework Statement Ok so we started Fourier Analysis in circuits. How can i tell the Period of a function that's let's say sin(2t)+3cos(5t) something like that . Any help or url's that have information on this
  12. M

    Calculating the Distance between the Feet of a Stepladder: Sin Rule & Pythagoras

    Homework Statement The two sides of a stepladder are of length 2m and 1.85m. When fully opened, the longer side is inclined at 65° to the horizontal. Find the distance apart of the feet of the step ladder. Homework Equations Sin Rule & Pythagoras? The Attempt at a Solution I had a go but I...
  13. R

    When to use cos or sin in physics problems

    Hi, I get really confused when to use the cos function or the sin function. for example, I was looking at this yesterday and thought the other way around of the correct answer. Why did it chose sin function for tension and cos function for the normal force? This problem doesn't explain why it...
  14. A

    How to Integrate sin(1 + cos^2 x)?

    First of all, hi I'm new here my name is crisanna. I stumbled upon this site across the web and realized this 's a great site! Anyway , here 's my question. Does anyone know how to integrate sin (1 +cos ^2 x) ? I tried the method integrate by parts but I got stucked. Below is my attempt : u=...
  15. M

    Integrating x^2 sin x: Find Exact Value of Abs(-pi/2 to pi/2)

    The question asks me to integrate x^2 sin x dx and then use it to find the exact value of the integration of abs ( x^2 sin x dx) with upper limit of pi/2 and lower limit of -pi/2. I have found the integration of x^2 sin x dx which is -x^2 cosx + 2xsinX + 2 cosx + C but after putting in the...
  16. icystrike

    Sin t = a+b, cos t = a-b, find tan t

    Homework Statement Im wondering if this question could be solved. Given that sin theta =a+b and cos theta =a-b Find tan theta when a/b=3 Solved alr.. the ans is 2. Homework Equations The Attempt at a Solution
  17. K

    Y = sin pi * x Arc Length/Surface Revolution

    Homework Statement y = sin \pix Using arc length and surface revoultion on x-axis 0 <= x <= 1 The Attempt at a Solution d/dx sin \pix = \pi cos \pix (\pi cos\pix)^2 = \pi^2 cos^2\pix \int sin pi * x * 2 * pi * \sqrt{1 + pi^2 * cos^2 (pi*x)} u = pi cos (pi * x) du = -pi^2 * sin...
  18. H

    Forgot how to graph sin graphs(translation)

    Ok so i have a function cos4/3x between 0<= X <= 2π the amp is 1, max is 1 and min is -1. the period is 3π/2. normally in a cos graph, π/2=0, π=-1, 3π/2=0 and 2π=1. but since the period is 3π/2, i know the 1 is now at 3π/2. But I am getting confused as to where the 0s and the negative -1...
  19. P

    Sin [Pi. (x-1)] / x-1; for x =1,2,3, .N

    Sin [Pi. (x-1)] / x-1; for x =1,2,3,...N Sin [ Pi. (x-1) ] / (x-1) = ? for x=1,2,3,4,...N I think for Sin (x) / x =1 but, what about that.
  20. P

    Sin wave Maximun/minimum finding?

    For different values of x in positive increasing order,sin wave would be either Max or Min, so I plotted all points.how to find out whether wave is max or min at a given particular point from X. Thanks.
  21. Q

    Maths question - multiplying by sin

    hi there. I have an expression Sqrt of 0.6 / 0.2 x sin ^2 however it is giving an error on the calculator. the equation am trying to work out is : x = 25 x 10 ^ - 9 x sin ^ - 1 (Square Root of 0.6 / 0.2 x sin ^ 2) (4 x 25)) / ∏ x 4 x 10 ^ - 6 how can I work out x when am getting...
  22. P

    Calculating large sums without Calculator (with sin)

    Homework Statement sin²(1°)+sin²(3°)+sin²(5°)+...sin²(359°)= ? And : 1!+2!+3!+4!+...+2006!, asked are he last two numbers of this sum. Homework Equations I don't know anyThe Attempt at a Solution I don't know how to calculate Sin with your head, and 2006! is way to hard to calculate. Is...
  23. G

    Exploring Non-Monotonic Functions: Does Sin n Apply?

    i understand that non monotonic is neither decreasing nor increasing does it mean sin n is also non monotonic ?
  24. S

    Deriving equation for circle using sin and cos identities

    Homework Statement I have been given these two equations: x=2acos^2(x) , y = 2a(cos(x))(sin(x)) where a ranges from 0 to 5 and -2π < x < 2π I need to prove that these equations (when you plug in values for x) create points that when plotted, give you a circle with center (x-a) and radius a...
  25. T

    Adding sin plus cos with fractions containing square roots

    How do I solve: [sin (pi/3)] + [cos (pi/6)]? <--- "pi" is 3.14... I think that [sin (pi/3)]= (square root 3) divided by 2 AND that [cos (pi/6)]= (square root 3) divided by 2. Now I can't remember how to add fractions containing square roots. My textbook...
  26. F

    Squeezing f(x) Between g(x) and h(x): Cos, Sin, & Tan

    f(x)=x4 cos(2/x6) g(x) <= f(x) <= h(x) how to get g(x) and h(x) by using the squeeze theorem?? I know is something like this -1 <= x <= 1 But how do i implement it here, and especially to the cos, sin, and tan??
  27. F

    Solving Sin() Function Problem: f(x) = 9 sin 7x, g(x) = 18 sin(7x + 5)

    f(x) = 9 sin 7 x, and g(x) = 18 sin(7 x + 5) so, i assume by looking just like this g(x) is twice much more than f(x) and 5 units more, correct??
  28. M

    How Do You Prove the Derivatives of Sin and Cos Functions?

    Hi. I believe this may have been addressed previously but I wanted to make sure since I don't think it was completed. Hi I know that differentiating sin = cos , and differentiating cos = -sin. Time to prove it. Q3: Prove that: \frac{d}{{dz}}\sin z = \cos z We know the McLaurin form...
  29. G

    Why Is Sin A Used in the Cross Product Equation F=qvBsinA?

    Homework Statement Just a general questions I don't understand. Why is it sin A in a cross product and not cos A? I don't understand it in the equation F=qvBsinA Homework Equations no The Attempt at a Solution ...
  30. T

    Derivative of y = sin x * cos x

    I'm working through Kline's Calculus book, and am at the chapter on Integration on Differentiation of Trig Functions. A question asks to find the derivative of: (I've labeled all equations for easy reference) (1) y = sin x * cos x unlike the solution guide which advocates using the product...
  31. S

    Calculate Area Difference of Triangles ABC with AB=5cm, AC=3.2cm

    soine cosine rule I have a question for you, I came across this question while revising for my exam on monday if anyone can answer this I'll be very impressed. Two different trangles ABC have AB=5cm, AC=3.2cm and angle ABC=35degrees calculate the difference between their areas.
  32. D

    How Do You Integrate \(\sin 6x + 3\cos 5x\) Using Substitution?

    Homework Statement Integrate \int\sin 6x + 3\cos 5x dx Homework EquationsThe Attempt at a Solution The way I was taught was the 'u' substitution method. I know that \int\sin u du = -\cos u + C and I know that \int\cos u du = \sin u + C Here's what I've done so far \int\sin 6x + 3\cos 5x...
  33. E

    Understanding the Sin Function

    [SOLVED] sin function Homework Statement My complex analysis book says, "from calculus, \sin \theta \leq \theta for 0 \leq \theta \leq \pi/2 ." Could someone please give me a better reason why that is true?Homework Equations The Attempt at a Solution
  34. E

    TRIG~ Law of Sin - Law of Cos HELP

    TRIG~ Law of Sin - Law of Cos HELP PLZ! hey i need some help... so umm please help me
  35. K

    Deriving x(t) into A sin (\omega*t + \varphi)

    Homework Statement Derive... x(t)=(exp^(-\zeta\omegat))*(a1(exp^(i\omegasqrt(1-\zeta^2)*t)))+a2(exp^(-i\omegasqrt(1-\zeta^2)*t)))) into x(t)=(exp^(-\zeta\omegat))*(A sin (\omega*t + \varphi)) Homework Equations n/a The Attempt at a Solution I've managed to get x(t) =...
  36. N

    How Accurate Is This Trigonometric Solution?

    Homework Statement 4sec180° - 2sin2270° The Attempt at a Solution sec(180 is -1. So we have 4(-1) which is -4 sin2(270 is -1 So we have 2(-1) This now reads -4 - -2 Answer = -2 Is this correct or do I suck at this? =(
  37. S

    Solving for t in a Trig Sin Function

    Greetings, I've solved (almost) a problem - with the answer involving sin(). My first solution involves values for which sin() is equal to 0.5 - i.e.30 degrees or 0.5235. The internal of the sin function is sin(10t -0.927) t = 0.1451 To complete this solution I need to show the...
  38. Pythagorean

    Is the Complex Conjugate of Sin Equal to Sin of the Conjugate?

    Homework Statement does (\sin{z})^* = \sin{z^*}? (where z is a complex number) Homework Equations \sin{z} = \frac{1}{2} (e^{iz} - e^{-iz}) The Attempt at a Solution (\sin{z})^* = \frac{1}{2} (e^{iz} - e^{-iz})^* = \frac{1}{2} (e^{-iz^*} - e^{iz^*}) = -\frac{1}{2} (e^{iz^*} - e^{-iz^*}) =...
  39. D

    How Do You Calculate Sine from a Point on an Angle's Terminal Side?

    urgent: sines if you are given a point on the terminal side of an angle 0 , explain how to find sin 0 Please i really need help with this one
  40. C

    Find, in terms of pi, the solutions of the equation sin5x + sin x = 0

    Hi. Could someone please help me with the following C3 question? I would really appreciate any help as I am completely stuck at the moment. Find, in terms of pi, the solutions of the equation sin5x + sin x = 0 for x in the interval 0 >= x > pi. I wrote down that sin(3x + 2x) + sin x = 0...
  41. C

    Understanding Cos and Sin: Tips for Using Trigonometry in Physics Problems

    Im having an issue of when to use Cos and Sin. When calculating Force (Normal and Frictional) with multiple demension problems you are typically given the angle of the incline. When trying to calculate for Fgx (or basically x) I would think to use cos(theta) and when dealing with Fgy (or...
  42. B

    What are the multiple solutions for sin x = 2/pi?

    Sin x = 2/pi How do you solve for x?? I am drawing a blank! I did sin-1 ( 2/pi) = 0.69 but I need another value cause I am also supposed to get 2.451?
  43. H

    Solving Sin & Cosin Law Homework | Find Angle Measure

    Homework Statement the question is Find the measure of the indicated angle, to the nearest tenth of a degree. Heres a picture of the question. (sorry for the bad quality) http://img107.imageshack.us/img107/7002/mathproblem2bb2.jpg ok for c) and d) I've applied what I've learned during the...
  44. K

    Prove that sin (n^2) + sin (n^3) is not a convergent

    Prove that \sin (n^2) + \sin (n^3) is not a convergent sequence.
  45. Saladsamurai

    Simplifying Trigonometric Integrals Using Trig Identities

    Okay so I am suposed to evaluate 2 of these: 1.) \int\sin^3(a\theta)d\theta the solution manual looks like it used a trig ID to do this. Why?? Doesn't \int\sin^3u du=\frac{1}{3}\cos^3u-(\cos u)+C ? So just use the u-sub u=a\theta \Rightarrow du/a=d\theta So it should just be...
  46. P

    Making a graph of acceleration vs. sin of theta

    Should I make acceleration the y-axis and sin of theta the x-axis or the other way around? If this adds to anything, as the sin of theta decreases, the acceleration is also decreasing...
  47. B

    Proof Inverse Sin: Complete Series Proof

    Can someone tell me where I can find a complete proof of the infinite series used to find the arcsin? thanks in advance.
  48. J

    What is the Frequency of an Alternating Current with a Sin Curve?

    Homework Statement what is the frequecy F for the alterating current U(T)=15cos(314t) A Homework Equations Am really new at this kind of problem but i think 314 is how many times the current rotates or fluxuates in 1 period so the F has to be the distance between waves? The...
  49. A

    Trigonometry sin and cos question

    My teacher told me that C sin(k x) + D cos(k x) = F sin(k x+gamma) if neither C nor D is 0 (gamma is a phase angle). How do you derive the expression on the right of the equal sign from that on the left?
  50. B

    Simplifying a product of sin functions

    can someone please simplify? \sin \frac{\pi}{n} \sin \frac{2\pi}{n} ... \sin \frac{(n-1)\pi}{n}
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