Trigonometry Definition and 664 Threads

I'm having problem with this question: From a point A, three straight lines are drawn to points R, S, T so that TRIANGLE ART is right-angled and points R , S, T are collinear. If AR = 12, AS=13, AT=37, determine the area of TRIANGLE AST. Is it ok to assume RAS and SAT is 45 degrees?

I found the area of this triangle to be 56.4 (to 3sf) easily but i can't work out the length of CX. any ideas?

do you guys know of any good online textbooks for high school-level algebra 2/trigonometry? the only thing that google gives me is either algebra 1 or college level lecture notes. how effective do you guys think online resources are for studying ahead

in part b) i of a question, i was asked to prove that (1-cos2x)/sin2x is equivilent to tanx and so i did. then in part b) ii i was asked to varify that 180 is a solution of x for: sin2x = 2 - 2cos2x i took the 2 out; sin2x = 2(1 - cos2x) and saw similarities to part i, so i divided by...

Trigonometry "puzzle" If we know the perimeter P of a triangle, a side S of it, and the height H down on the line going through S, then we have uniquely determined the triangle. It is not wholly trivial to derive the expressions for the other two sides in terms of P,S and H.

I've been staring at this question for about 4 hours and i am conviced there is some missing data in the question because its just impossible. this is the question "a uniform strip of wood 5.0 cm wide frames a trapezoidal window, as shown in fig 4.84. Find the left dimension "x" of the...

ABC is right angled at B. Prove that tanA+tanC=b^2 / ac Ok so far I've got that tan A= a/c and tanC=c/a and then when i try to add those together i get (c^2)(a^2)/ac , but how can (c^2)(a^2) = b^2 all I've thought of is pythagorus's theorem. But for it to equal b^2, a^2 has to be...

The voltage E applied to the sending end of a high-pressure transmitting line is connected to the voltage e at the receiving end by the equation E^2=(e*cos(x) + a)^2 + (e*sin(x) + b)^2, where a and b are constants. Expand the right-hand side of the equation and by expressing a*cos(x) +...

Ok i need help to calculate the co-efficients of certain terms in the binomial expansion for example: (3 + (5/X)^2)^10 what is the coefficient of x^8? I hope that question works sorry if it doesn't i did just make it up then... if you know of any like it please help! also, an...

1.) sin2x=3cos2 2.) (3tan2x-1)(tan2x-3)=0 3.) cos3x=cosx 4.) 3tan3x=tanx Those were a few of the problems in the section I missed on friday due to illness and I was wondering if anyone could walk me through them. Would be greatly appreciated! They want to solve the equation for...

Find all the points on the graph of the function f(x) = 2 \sin x + \sin^2 x at which the tangent is horizontal. f'(x) = 2 \cos x + 2 \sin x \cos x = 0 2 \cos x (1 + \sin x) = 0 \cos x = 0 or \sin x = -1 x = \frac{\pi}{2} + n\pi or x = \frac{3\pi}{2} + 2n\pi I then plug into find the...

The problem is Solve sin(2y)=cos(4y) for y, where \\0\leq y \leq 360 This one is tricky, I want to try to equate either sin to cos or cos to sin so I can work with only one trig function, but how? I don't see how to start this problem. I know that the period of sin2y is 720deg or 4pi, and...

Hello, I am currently in beginning physics and we are learning a lot about Trig onometry. A homework problem is really bugging me. Here's what it says: Find the angle A, given the altitude and arc length of the figure shown: (the picture is in the attachment and also some work i have done.)

Because Trigonometry is a pre-requisite for Calculus, the purpose of this procedure is for use in 'calculator banned' Calculus courses, to eliminate the requirement of memorizing sixteen 'special angles' in Trigonometry to derive the correct solution. Memorizing this procedure can produce all...

hey i have a problem which I am puzzled over. i I am given that: \sin A = \frac{3}{5} and i am asked to find exact values for: \sin 2A \cos 2A \tan 2A where 90^0 \leq A \leq 180^0 (the power to zero is the degree sign) i have gone about solving this by the use of a pythagorien (?) triple...

i need to prove the following identity \sin^4 - \cos^4 = 1 - 2\cos^2 i have tried approaching this identity by solving the RHS (right hand side) of the equation but this lead no where. however i am unsure on how to maniplulate the LHS of this equation because of the power of 4. would...

Is it possible to integrate a trigonometry function within a function, or is this a formula that cannot be integrated in terms of elementary functions? \int \sin(\cos x) dx

Pleas help! exam tommarow! Trigonometry word problems Hi, i really need help with this question, on a wall, a spider is 100cm above a fly. the fly starts moving horizontally at the speed of 10cm/s. After 1s, the spider begins moving at twice the speed of the fly, in such a way as to...

Could someone check this for me and help answering the questions at the end The 3 angles around point 6 are 120 degrees each. This is also the case for point 8 which is linked to point 2, 3 and 7. Now the 3 angles formed by the lines leaving point 7 are also 120 degrees. If the distance...

Hello, I'm brand new here; needless to say, I think it's great what this community is doing. Now to my question: my class is just finishing up geometry, which means we're starting to enter into beginning trig. Here's the problem: 1-Sinx/1+Sinx = (Secx-Tanx)^2 So far, I've been able...

I understand how trigonometry is related to the Unit Circle, but is there any way I can relate the same concept to circles with a radius other than 1? Thanks in advance. :biggrin:

y' = 2y/x + x cos (y/x^2), with y=z*x^2 => y' = 2zx + x cos z and y=z*x^2 => y' = 2zx + x^2 * dz/dx So that leaves x^2 * dz/dx = x cos z => dz/cos z = dx/x I integrate both sides so that: sec z + tan z = x + C But I don't have a clue on how to get past that point. Should I start...

Trigonometry made more "rational" I read an article the other day on "rational trigonometry" and decided to go exploring... and I feel as if a lightbulb has turned on. This seems like such a wonderful new technique to doing otherwise cumbersome problems, and I agree that it does feel like a...

I recently was given an assignment to find three interactive websites that refer to sine, cosine, and tangent. This wouldn't be a problem... if it weren't for the fact that the laptops they are required to run on do not have Java, and cannot load the applets. I need the URLs for these sites by...

I have reduced a problem I am trying to solve to something simpler though rather difficult: Four side lengths and an angle uniquely describe a quadrilateral, solve one of the angles adjacent to the one given. No matter what algebraic / trigonometric manipulations I apply I cannot get a...

How would you, to the best of your abilities, explain to someone like me how trigonometry functions emerged? I'm not in any way or form an advanced mathematics student and in this specific subject I only know the basics of the very basics (i.e how to find the sides and angles of right...

I have read that astronomers are responsible for much of the advances in trig hundreds of years ago but never seem to find who exactly pioneered this field of research.

im trying to remember how to do some trig. first of all, how do you find cos^-1 (5/3) without using a calculator? 2nd, i need help proving this identity: 2sin^2(x) - cos (x) - 2 sin (x) + 1 = 0 3rd, how do you evaluate sin 165 (which is sin (11/12 pi)) again without using a...

http://physorg.com/news6555.html :!) :!) :!) :!) :!) could this be the second coming?

http://physorg.com/news6555.html Discuss.

I haven't been here for a long time, so sorry if this was already posted: http://physorg.com/news6555.html Dr Norman Wildberger has devised a new method of trigonometry that gets rid of sin, cos, tan (and the like) functions and uses algebra instead. It's supposedly straight forward, more...

How do I go about finding the equivalent expression for cot 50 degrees? When I work the problem, I come up with tan 130 degrees. Where am I going wrong?

I am having extreme difficulty with my Trigonometery homework. In particular, When I simplify the expression: cos2xsin2x-cos2x I come up with cos2x. This is obviously incorrect. Where am I going wrong?

I am really stumped! Using only Trigonometry, I am suppose to calculate the amount of force that is needed to keep a 2000 lb car from rolling down a ramp of 30 degrees. Am I on the right track when I say: x=2000cos 30? Then what?

I'm really struggling with the following question: A river running due east has straight parallel banks. A vertical post stands with its base, P, on the north side of the river. On the south bank are two surveyors, A who is to the east and B who is to the west of the post. A & B are at a...

it was a one semester class, so it is basic. note: i will not cover graphing and inverse trig function. i will begin by introducing a unit of measurement of angles, because i find them much easier to work with. that unit is radian. the name will make sense after the description. we have a...

Can someone break down in "baby steps" how to solve the following?: cos7pi/6=? thank you. :rolleyes:

I have a straight-forward question. Could anybody please explain me why... \theta = \tan ^{-1} \left( \frac{x}{2} \right) \Rightarrow -\frac{1}{4\sin \theta} = -\frac{\sqrt{x^2+4}}{4x} Thanks

I'm looking for a trigonometry book that is rigorous, concise, insightful, etc. Something along the lines of Euclid's Elements, Spivak's Calculus, Rudin's Principles. I understand it's usually taught at the high school or college freshman level, but I'd like a book that someone who already knows...

Hi everyone, I'm sorry to bother you with such a trivial question but I really am stuck here. I don't know why I can't prove this one as I've managed to get harder ones than this, but as it is I need help with it. This is the question: Prove 1-cos2x+sin2x = tanx...

I've been stuck on this question for awhile. Q: Square numbers 1, 4, 9, 16, 25... are the values of the function s(n)=n^2, when n is a positive integer. The triangular numbers t(n)=(n(n+1))/2 are the numbers t(1)=1, t(2)=3, t(3)=6, t(4)=10. Prove: For all positive integers n, s(n+1) = t(n)...

Prove that the triangle ABC is: a) acute, if and only if tan(alfa)*tan(beta)>1 b) right, if and only if tan(alfa)*tan(beta)=1 c) obtuse, if and only if tan(alfa)*tan(beta)<1

I am studying calculus on my own, and I just skip everything to do with trigonometry. I have never done trigonometry before(except just the basic ratios), and I was wondering whether you really need to study trigonometry before calculus. I see a lot of trigonometry in my calculus book, and I...

I'm new to trigonometry, but I think I know the basics - soh cah toa ect. If I want to find the angle of the pendulum first then I need to do: Sin-1 * (opp / hyp) However I haven't got the hypotenuse, but the adjacent. So am I right to firstly work out the hypotenuse by opposite2 +...

A force vector F1 points due east and has a magnitude of 200N. A second force F2 is added to F1. The resultant of the two vectors has a magnitude of 400N and points along the east/west line. Find the magnitude and direction of F2. i really don't know what equation I would use to solve this...

sin^8(x) + cos^8(x) = 97 / 128

The question says determine theta I have a triangle with a hypotenuse of 3 cm opposite the angle theta is 2cm length and adjacent to that is unknown. I don't know how to solve this question I don't remember what theta is lol or how to punch it in the calculator what do I do please help...

I'm trying to review spherical trinometry on my own and I'm stuck where it says the supplement of the solved dihedral angle can be implemented. I'm using "PLANE AND SPHERICAL TRIGONOMETRY" by Paul Rider. Can anyone explain the concept behind that statement, because the examples that I have are...

Someone pls help me prove this identity. I'm going nuts :confused: tan^2x - sin^2x = tan^2x sin^2x

I have basic trignometry doubt how to u get 5cos(2t-53.13degrees) from 3cos2t + 4 sin2t. Can someone suggest a site from where I can lean basic trinometry thanks. skan