John Joy's user avatar
John Joy's user avatar
John Joy's user avatar
John Joy
  • Member for 9 years, 6 months
  • Last seen more than a week ago
  • Hamilton, ON
57 votes

How to prove that $\lim\limits_{x\to0}\frac{\sin x}x=1$?

49 votes

How can I evaluate $\sum_{n=0}^\infty(n+1)x^n$?

27 votes
Accepted

How do I determine if the following function is periodic?

18 votes

Inequality with (1-x) as denominator

15 votes
Accepted

How to make a "function"?

15 votes

Why does cross product give a vector which is perpendicular to a plane

13 votes

Show that: $\sinh^{-1}(x) = \ln(x + \sqrt{x^2 +1 } )$

11 votes
Accepted

which is larger: $\sin(4^\circ)$ or $2\sin(2^\circ)$?

9 votes

how to find surface area of a sphere

9 votes

Proving the identity $\sum_{k=1}^n {k^3} = \big(\sum_{k=1}^n k\big)^2$ without induction

8 votes

Taylor expansion, integration by parts, and the integration of dt.

8 votes

How is $x \leq x^2$ false?

7 votes

Find the number of bicycles and tricycles

6 votes

Evaluate $\int{\frac{1}{\sin x + \cos x}}dx$

6 votes

Is there a chain rule for integration?

6 votes

Find the value of $\sin(90-a)$

6 votes

Algebraic proof of $\tan x>x$

5 votes

Prove that $\lim_{x\rightarrow 1}{\frac{x^n-1}{x-1}}=n$ for all integer n without L'Hôpital

5 votes
Accepted

Is $\frac{5x}{3}$ The Same As $\frac{5}{3}x$?

5 votes

$\sec\theta$ never equals $\tan\theta$. Or does it?!?

5 votes

Another way proof $1/2-1/3=1/6$ by using picture?

4 votes

How to know that $2n^3+9n^2+13n+6$ factors into $(n+1)(n+2)(2n+3)$?

4 votes

$\lim_{x\to 0} \frac{1-\cos(x)}{x\cos(x)} $ without L'hopital

4 votes

Integration being the opposite of differentiation?

4 votes

Can an inflection exist if there's no max/min?

4 votes

Proving $1^3+ 2^3 + \cdots + n^3 = \left(\frac{n(n+1)}{2}\right)^2$ using induction

4 votes
Accepted

a geometric interpretation of a line integral

4 votes
Accepted

Basic trigonometry identities question

3 votes

Proof that $1+2+3+4+\cdots+n = \frac{n\times(n+1)}2$

3 votes

How to memorize the trigonometric identities?

1
2 3 4 5
18