Search found 102 matches

by jacks
Wed Jul 13, 2016 8:07 am
Forum: Real Analysis
Topic: maximum value of \(f(y)\)
Replies: 1
Views: 1869

maximum value of \(f(y)\)

Maximum value of $$\int_{0}^{y}\sqrt{x^4+\left(y-y^2\right)^2}dx\;,$$ Where \(y\in \left[0,1\right]\)
by jacks
Wed Jul 13, 2016 7:46 am
Forum: Calculus
Topic: floor function integral
Replies: 5
Views: 4581

Re: floor function integral

My Try for (1):: Let \(\displaystyle I = \int_{0}^{\pi}\lfloor \cot x \rfloor dx\;,\) Now using \(\displaystyle \int_{0}^{a}f(x)dx = \int_{0}^{a}f(a-x)dx\) So we get \(\displaystyle I = \int_{0}^{\pi}\lfloor -\cot x \rfloor dx\;,\) So we get \(\displaystyle I = \int_{0}^{\pi}\left(\lfloor \cot x \rf...
by jacks
Wed Jul 13, 2016 7:40 am
Forum: Calculus
Topic: floor function integral
Replies: 5
Views: 4581

floor function integral

(1) Evaluation of \(\displaystyle \int_{0}^{\pi}\lfloor \cot x \rfloor dx\;,\) where \(\lfloor x \rfloor \) is floor function of \(x\).

(2) Evaluation of \(\displaystyle \int_{0}^{\pi}\lfloor \cos x \rfloor dx\;,\) where \(\lfloor x \rfloor \) is floor function of \(x\).
by jacks
Wed Jul 13, 2016 5:41 am
Forum: Calculus
Topic: 2 logarithmic Integral
Replies: 4
Views: 4145

2 logarithmic Integral

$(a)\;$ Evaluation of $\displaystyle \int_{0}^{\sqrt{2}-1}\frac{\ln(1+x^2)}{1+x}dx$

$(b)\;$ Evaluation of $\displaystyle \int_{0}^{1}\frac{\ln(1+x^2)}{1+x}dx$
by jacks
Wed Jul 13, 2016 5:39 am
Forum: Calculus
Topic: Two Trig Integral
Replies: 0
Views: 1671

Two Trig Integral

$(a)\;\;$ Evaluation of $\displaystyle \int \sqrt{\tan^2 x-3}\; dx$

$(b)\;\;$ Evaluation of $\displaystyle \int \sqrt{\tan x+3}\; dx$
by jacks
Tue Jul 12, 2016 9:44 am
Forum: Calculus
Topic: Trig. Indefinite Integral
Replies: 1
Views: 1895

Trig. Indefinite Integral

Evaluation of \(\displaystyle \int e^{x\sin x+\cos x}\cdot \left(\frac{x^4\cos^3 x-x\sin x+\cos x}{x^2\cos^2 x}\right)dx\)
by jacks
Tue Jul 12, 2016 8:32 am
Forum: Real Analysis
Topic: Sum of series
Replies: 2
Views: 2300

Re: Sum of series

Let $$S = \sum _{ m=1 }^{ \infty }{ \sum _{ n=1 }^{ \infty }{ \frac { { m }^{ 2 }n }{ { 3 }^{ m }(n{ 3 }^{ m }+m{ 3 }^{ n }) } } } $$ Using the fact that $$\sum_{m = 1}^\infty\sum_{n = 1}^\infty f(m,n) = \sum_{m = 1}^\infty\sum_{n = 1}^\infty f(n,m) $$ we can rewrite \(S\) as $$S = \sum _{ m=1 }^{ \...
by jacks
Tue Jul 12, 2016 4:25 am
Forum: Real Analysis
Topic: Solution of Differential equation
Replies: 1
Views: 1857

Solution of Differential equation

If \(\displaystyle y'(x)+y(x)\cdot g'(x) = g(x)\cdot g'(x)\;,y(0)=0\;,x\in \mathbb{R}\;,\) If \(\displaystyle f'(x) = \frac{d}{dx}\left(f(x)\right)\) and \(g(x)\) is a non constant differentiable function on \(\displaystyle \mathbb{R}\) with \(g(0) = g(2) = 0\;\). Then the value of \(y(2)\) is?
by jacks
Tue Jul 12, 2016 4:19 am
Forum: Calculus
Topic: 2 Indefinite Integrals
Replies: 4
Views: 3292

Re: 2 Indefinite Integrals

Grigorios Kostakos wrote:Jacks, your result for \((2)\,(a)\) it is not correct: Assuming \(a\neq b\) you must have that: \[\displaystyle \int\frac{\sin^2 x}{a^2\sin^2 x+b^2\cos^2 x}dx=\frac{1}{a^2-b^2}\Bigl({x-\frac{b}{a}\arctan\bigl({\tfrac{a}{b}\tan{x}}\bigr)}\Bigr)\]
Thanking You Grigorios Kostakos, Got my mistake.
by jacks
Tue Jul 12, 2016 4:15 am
Forum: Calculus
Topic: 2 Indefinite Integrals
Replies: 4
Views: 3292

Re: 2 Indefinite Integrals

I have evaluate \((a)::\) Given \(\displaystyle \int\frac{\sin^2 x}{a^2\sin^2 x+b^2\cos^2 x}dx = \frac{1}{a^2}\int \frac{a^2\sin^2 x}{a^2\sin^2x+b^2\cos^2 x}dx\) Divide both \(\bf{N_{r}}\) and \(\bf{D_{r}}\) by \(a^2\cos^2 x\;,\) We Get \(\displaystyle =\frac{1}{a^2}\int\frac{\tan^2 x}{\tan^2 x+A}dx...