User ABC

9 votes

11 answers

24k views

Prove $ax^2+bx+c=0$ has no rational roots if $a,b,c$ are odd

quadratics

asked Mar 24, 2013 at 14:08

7 votes

3 answers

2k views

Trigonometric function integration: $\int_0^{\pi/2}\frac{dx}{(a^2\cos^2x+b^2 \sin^2x)^2}$

integration definite-integrals

asked May 25, 2013 at 17:26

4 votes

3 answers

139 views

Prove $P(x)>0, \forall \space x>1$

real-analysis

asked Mar 22, 2013 at 11:13

4 votes

1 answer

89 views

How many natural numbers $n$ exist for $n=a^2−b^2−c^2$

algebra-precalculus

asked Mar 30, 2013 at 9:06

4 votes

3 answers

213 views

Rank of a matrix.

matrices

asked Apr 4, 2013 at 10:51

4 votes

3 answers

257 views

Finding the maximum of $\frac{a}{c}+\frac{b}{d}+\frac{c}{a}+\frac{d}{b}$

inequality optimization

asked Apr 11, 2013 at 11:59

3 votes

4 answers

142 views

Differential Equation @ 2nd Order

ordinary-differential-equations

asked Apr 6, 2013 at 4:29

3 votes

2 answers

3k views

How to prove $\int f (x)dx\times \int g(y)dy =\iint f(x)\cdot g(y)\, dx\, dy$

calculus integration

asked Apr 8, 2013 at 17:19

3 votes

2 answers

2k views

Triangle $\Delta ABC$ , $a,b,c$ are in G.P.

inequality triangles

asked Mar 24, 2013 at 16:49

3 votes

3 answers

130 views

Maximum value of $Z$

complex-numbers

asked Mar 28, 2013 at 11:58

2 votes

2 answers

167 views

Evaluate $\int \frac{\sin^{-1}\sqrt{x}}{\sqrt{1-x}}\,dx$

calculus integration indefinite-integrals

asked Mar 21, 2013 at 16:56

1 vote

2 answers

102 views

Evaluate a big expression.

integration limits definite-integrals

asked Mar 21, 2013 at 17:16

1 vote

1 answer

192 views

How to find $\frac{d^2x}{dy^2}$

functions derivatives

asked Apr 1, 2013 at 10:26

1 vote

1 answer

518 views

Improper integral evaluates to $-\pi^2/12$

integration definite-integrals

asked Mar 22, 2013 at 12:01

1 vote

2 answers

376 views

Differential Equation $y'-P(x)y=Q(y)$

ordinary-differential-equations

asked Mar 23, 2013 at 5:15

1 vote

3 answers

131 views

How to find remainder?

number-theory

asked May 25, 2013 at 6:11

0 votes

1 answer

361 views

Sum $\sum \frac{1}{n}\not \in N$ [duplicate]

sequences-and-series summation

asked Mar 24, 2013 at 2:50

0 votes

2 answers

89 views

How to tackle questions involving count?

combinatorics

asked Mar 24, 2013 at 17:17

0 votes

1 answer

191 views

Calculate the time after which Money doubles

algebra-precalculus finance

asked Apr 1, 2013 at 17:04

0 votes

2 answers

136 views

Calculate $|X|$, where $X=(A+A^2B^2+A^3+A^4B^4\dots _{100 \ terms})$

matrices determinant

asked Apr 12, 2013 at 11:51

0 votes

0 answers

53 views

What is the problem? [duplicate]

geometry paradoxes

asked Apr 22, 2013 at 14:40

-1 votes

3 answers

92 views

Find the min value of $3a+b$

quadratics

asked Mar 25, 2013 at 16:06

-2 votes

1 answer

706 views

Finding torque of a force [closed]

vector-spaces physics

asked May 26, 2013 at 17:25

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23 Questions

Prove $ax^2+bx+c=0$ has no rational roots if $a,b,c$ are odd

Trigonometric function integration: $\int_0^{\pi/2}\frac{dx}{(a^2\cos^2x+b^2 \sin^2x)^2}$

Prove $P(x)>0, \forall \space x>1$

How many natural numbers $n$ exist for $n=a^2−b^2−c^2$

Rank of a matrix.

Finding the maximum of $\frac{a}{c}+\frac{b}{d}+\frac{c}{a}+\frac{d}{b}$

Differential Equation @ 2nd Order

How to prove $\int f (x)dx\times \int g(y)dy =\iint f(x)\cdot g(y)\, dx\, dy$

Triangle $\Delta ABC$ , $a,b,c$ are in G.P.

Maximum value of $Z$

Evaluate $\int \frac{\sin^{-1}\sqrt{x}}{\sqrt{1-x}}\,dx$

Evaluate a big expression.

How to find $\frac{d^2x}{dy^2}$

Improper integral evaluates to $-\pi^2/12$

Differential Equation $y'-P(x)y=Q(y)$

How to find remainder?

Sum $\sum \frac{1}{n}\not \in N$ [duplicate]

How to tackle questions involving count?

Calculate the time after which Money doubles

Calculate $|X|$, where $X=(A+A^2B^2+A^3+A^4B^4\dots _{100 \ terms})$

What is the problem? [duplicate]

Find the min value of $3a+b$

Finding torque of a force [closed]