So I'm trying to get through euler's introduction to the analysis of the infinite so I could eventually read his books on calculus but I'm stuck somewhere and can't seem to figure out how he equates this identity
so by expanding I get sin(2y) * cos(z) + cos(2y) * sin(z).
I get that the...
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Express in the form a + bi, where a and b are real numbers.? - Yahoo! Answers
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"Sum to Product" Trigonometric identity does not work
Hi,
The identity
sin(u) + sin(v) = 2 * sin (\frac{u+v}{2}) * cos(\frac{u-v}{2})
http://en.wikipedia.org/wiki/List_of_trigonometric_identities#Product-to-sum_and_sum-to-product_identities
Does not always work. I put the equation :
(sin(u)...
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Homework Statement
Given (e^(ix) - 1)^2 , show that it is equal to 2-2cosx
Homework Equations
e^ix = cosx + isinx
The Attempt at a Solution
After subbing in Euler identity and expanding I get:
cos(x)^2+sin(x)^2-2cosx-2jsinx+2jcosxsinx + 1
after using the addtion formulas I get...
Homework Statement
Can you all help?
The problem is 2 sin(x/2) - 1 = 0 I don't know what to do with the (x/2).
The Attempt at a Solution
So far I've done this:
2 sin(x/2)-1=0
2 sin(x/2)=1
sin(x/2)=1/2
1. The problem statement
Find the sum of the series:
a. 1 + a cos θ + a^{2} cos 2θ + a^{3} cos 3θ + ... + a^{n} cos nθ
Apparently, the answer is:
\frac{a^{n+1}(a cos nθ - cos(n+1)θ) - a cos θ + 1)}{a^{2} - 2a cos θ + 1}
2. The attempt at a solution
= The real part of z^{0} +...
Homework Statement
Given the following two triangles:
Show that v \cos{\delta} = V(1-\cos{\beta})+u\cos(\alpha - \beta)
The Attempt at a Solution
Using the cosine law I've got:
v^{2}=x^{2}+V^{2}-2xV\cos{(\theta + \beta)}
and u^{2}=x^{2}+V^{2}-2xV\cos{(\theta)}
I figured maybe using the...
Homework Statement
Let R = \{ (x,y) \in \mathbb{R^{2}}: 0<x<1, 0<y<1\} be the unit square on the xy-plane. Use the change of variables x = \frac{{\sin u}}{{\cos v}} and y = \frac{{\sin v}}{{\cos u}} to evaluate the integral \iint_R {\frac{1}
{{1 - {{(xy)}^2}}}dxdy}
Homework Equations...
Find x such that trigonometric \dfrac{\sin (3x) \cos (60^{\circ}-x)+1}{\sin (60^{\circ}-7x)-\cos (30^{\circ}+x)+m}=0 where m is a fixed real number.
Hi all, I know the expression in the numerator has no real roots by checking it at W|A (plot the graph of y=sin(3x)cos(pi/3 -x)+1 -...
Homework Statement
When integrating a function of the form:
\displaystyle\int_c^d { (sinx)^{a} * (cosx)^{b}}
Is this a correct simplification of the rules to evaluate:
1. if exponent on sin or cos is odd, and the other is even, separate out one of the odd's and use
an identity on the...
Homework Statement
(question attached)
Homework Equations
The Attempt at a Solution
Checking solution.. pretty sure I did this wrong.
(solution attached)
Homework Statement
Simplify the following trigonometric expression:
cscθtanθsecθ
Homework Equations
tanθ = sinθ/cosθ
sin^2θ + cos^2θ = 1
cscθ = 1/sinθ
secθ = 1/cosθ
cotθ = 1/tanθ
The Attempt at a Solution
I just want to double check my solution.
cscθtanθsecθ = 1/sinθ x...
I have shown the first part that they ask for.
For the second part:
let tanθ = t
tan(3\theta) = \displaystyle\dfrac{tan(2\theta) + tan\theta}{1-tan(\theta)tan(2\theta)} = \dfrac{\frac{2t}{1-t^2} + t}{1 - t(\frac{2t}{1-t^2})}
hence t = 2 + \dfrac{3t - t^3}{1-3t^2}
t^3 - 3t^2 + t + 1...
Homework Statement
Sin(tan(2x))
With respect to x
Homework Equations
Differentiation
The Attempt at a Solution
My question is whether I can simply use d/dx (Tan x) = Sec^2(X) to extrapolate that to d/dx(tan 2x) = Sec^2(2x) ?
Or do I have to convert to sine/cosine and go from...
Hello,
I got problem with A homework
"find an equation of the tangent line to curve at the given point.
$y=sec(x)$. $(pi/3,2)$
progress:
$y'=sec(x)tan(x)$. So basicly that sec(x) don't say me much so i rewrite it as $1/cos(x)$
$y'=1/cos(x)•tan(x)$ now i can put $pi/3$ on the function to...
Homework Statement
g(x) = 4∏ [cos(3∏x) sin (3∏x)]The Attempt at a Solution
g(x) = 4∏ [cos(3∏x) sin (3∏x)]'
4∏{[cos (3∏x)][sin(3∏x)]' + [sin(3∏x)][cos(3∏x)]'} =
4∏{[cos (3∏x)][cos(3∏x) . (3∏)] + [sin(3∏x)][-sin(3∏x) . (3∏)] =
Now, my question is: Can I combine the numbers and have the...
Hello,
Im currently on chapter about derivate trigonometric functions. It have been hard for me to understand this sec,cot,-csc? Why do you rewrite example $1/cos^2x$ as $sec^2x$? when I get like sec,csc etc i kinda feel i have no clue what it means. Then you think what do Petrus mean? example I...
Find y^{I} (sinxsecx)/1+xtanx The supplied answer is 1/(1+xtanx)^{2}
I got stuck with an extra x on top at the end. Where did I mess up at?
y^{I}(sinxsecx)/1+xtanx = [1+xtanx*f^{I}(sinxsecx)-sinxsecx*f^{I}(1+xtanx)]/(1+xtanx)^{2} =...
Homework Statement
evaluate the integral.
Homework Equations
integral (pi/6 to pi/4) [(sin2x)^4 / sqrt(1-cos2x) dx]
The Attempt at a Solution
1. multiplying by conjugate: sqrt(1+cos2x)/sqrt(1+cos2x) .
2. should i split the (sin2x)^4 into (1-(cos2x)^2)^2 ?
Homework Statement
solve the integral.Homework Equations
integral (5pi/6 to pi) (cosx)^4 / sqrt(1-sinx) dxThe Attempt at a Solution
Following the solution manual:
integral (5pi/6 to pi) ( (cosx)^4 / sqrt(1-sinx)) * sqrt(1+sinx)/sqrt(1+sinx)
however i am not sure how to do the algebra here...
Homework Statement
integral (1)/(x^2sqrt(36-x^2)
Homework Equations
The Attempt at a Solution
I found X=6sinθ dx=6cos
√(36-x^2)=√(36-sin^2θ)=6cosθ
i think the problem is that i am not getting integral of ∫csc^2θ
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I am unsure whether I have properly performed the integration of the integral ∫((sin(√x))^3*dx)/√x
When I used my TI-Nsprire CAS to take the derivative of my answer in order to check if I was correct, and it came out differently. Now I used some trig identities to manipulate the problem, so I...
Homework Statement
evaluate the definite integral ∫(0 to 3) dx/sqrt(25+x^2)
Homework Equations
The Attempt at a Solution
I first used substitution and set x=5tanθ, and dx=5tanθsecθdθ
then i wrote the integral as 5∫ tanθsecθdθ/sqrt(25(1+tan^2(θ))
after some simplification i...
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Solve for x in the equation 1+sinx/cosx + cosx/1+sinx = 4 for 0 < x < 2pi? - Yahoo! Answers
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Please consider the following equation:
$\displaystyle \sum_{k=1}^{n}\cos^4\left(\frac{k\pi}{2n+1} \right)=\frac{6n-5}{16}$
For this particular equation, which I am trying to prove is true, I have found no way to crack it, even if I let $n=2$ and begin to try to combine the terms together...
I want to prove this equation:
\cos\left(\frac{2\pi}{5}\right)+\cos\left( \frac{4\pi}{5}\right)+\cos\left( \frac{6\pi}{5}\right)+\cos\left(\frac{8\pi}{5} \right) = -1 .
I've no idea how to begin. I think it may be related to complex numerd but I don't know how to combine them.
Homework Statement
Show, using complex numbers, that sin(x)+cos(x)=(√2)cos(x-∏/4)
Homework Equations
cos(x)=(e^(ix)+e^(-ix))/2
sin(x)=(e^(ix)-e^(-ix))/2i
e^ix=cos(x)+isin(x)
The Attempt at a Solution
I was given the hint that sin(x)=Re(-ie^(ix)), but have thus far not been...
Homework Statement
Solve
cot^{-1} x - cot^{-1} (n^2 - x+1)=cot^-1(n-1)
Homework Equations
The Attempt at a Solution
I can write the above equation as θ+α=β where the symbols represent the respective inverse functions. Now I take tan of both sides. Simplifying I get...
My task is to solve the integral \frac{1}{\cos 2z} on the contour z=|1| using a Laurent series.
The easy part of this is the geometric part. I drew a picture of the problem. I see that there are two singularity points that occur within the contour region at \pm \frac{\pi}{4}. I realize...
Studying for finals here...So I have this specific problem to use trig substitution on.
$$\int \frac{x^2}{\sqrt{1-x^2}}\,dx$$
I begin by substituting
$$x={sin{\theta}}$$
I am fine with doing everything up to the point where I have an answer for the integral in terms of \(\theta\). This...
I have always capitalised the first letter of my trigonometric functions, for example, writing Sinθ as opposed to the usual sinθ. Is it wrong to capitalise them? Does it make a difference in meaning?
Homework Statement
Express the function f(x) = -2sin(3x) -4cos(3x) in the form of a general sine finction.
Identify the amplitude, period, and phase shift
Homework Equations
sinx/cosx = tanx
sin2x + cos2x = 1
The Attempt at a Solution
don't know how to start
don't...
Homework Statement
Solve each equation for solutions on the interval 0 ≤ x ≤ 2∏.
2 sin x = √3
The Attempt at a Solution
Okay so I was able to solve this one:
2 sin x = √3
sin x = (√3) / 2
So i got x = ∏/3 ; 2∏/3 ; 4∏/3 ; 5∏/3
I substituted the x's into the original...
Homework Statement
Find the exact value of the given expressions.
sin (2 sin-1 (4/5))
or
sin (2 arcsin (4/5))
Just two different ways of writing it
Homework Equations
maybe
The Attempt at a Solution
I've only gotten this far:
sin (2 arcsin (4/5)) = 2 sin (arcsin (4/5))...
Homework Statement
Given the equivalent impedance of a circuit can be calculated by the
expression
Z= (Z_1 Z_2)/(Z_1+ Z_2 )
If Z1 = 4 + j10 and Z2 = 12 – j3, calculate the impedance Z in
both rectangular and polar forms.
Homework Equations
j2=-1
The Attempt at a Solution
Z=...
Homework Statement
Show that:
∫f(sin(x))dx = ∫f(cos(x))dx
where each integral is over the limits [0, \pi/2], for a 'well behaved' function f.
2. The attempt at a solution
I have tried relating sin(x) and cos(x) and somehow rearrange one of the integrals to look like the other. Since...
Homework Statement
tg(4x) = 1
The Attempt at a Solution
I have a doubt about the part I have to add to the result, are these solutions correct ?
4x = 45° + n * pi
x = 11,25° + n * (pi/4)
Thanks