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visits member for 3 years, 3 months
seen Dec 14 at 21:03

Oct
2
comment Rate of increase in the area of a square
@jordan there really are only three essential symbols in pedja's answer: $P$ , $a$ , and $t$. $P$ is the area of the square, $a$ is the side length, and $t$ is just your time variable. $dP$, for example, is just shorthand to say, "the change in P" However, that's pretty meaningless without knowing what P is changing relative to. So, we write $\frac{dP}{dt}$, meaning the change in P relative to the change in t. $\frac{da}{dt}$ follows a similar pattern Pedja's first step, then, is implicit differentiation of the area formula $P = a^2$. From there, everything is replaced by givens.
Oct
2
revised Rate of increase in the area of a square
spelling correction, clarity
Oct
2
suggested approved edit on Rate of increase in the area of a square
Oct
1
revised Which loan type is cheapest?
clarity & grammar
Oct
1
suggested approved edit on Which loan type is cheapest?
Oct
1
answered Equation of a rectangle
Sep
29
comment Calculating edge coordinates of arrowhead. (pretty basic trigonometry)
You're welcome, glad to help.
Sep
27
answered Calculating edge coordinates of arrowhead. (pretty basic trigonometry)
Sep
27
comment Combinatorics - Building strings with symbols from two alphabets
No worries. Just jumped out as a book problem.
Sep
27
awarded  Commentator
Sep
27
revised Economics formula
removing overzealous HW tag
Sep
27
suggested approved edit on Economics formula
Sep
27
comment Calculating edge coordinates of arrowhead. (pretty basic trigonometry)
I think @pic has the right idea. Alternatively, you could repharse the same problem as vector addition. Namely, have A to B be a vector, and create a vector each for the left and right edges of the arrow head. Given b, the angle of the body of the arrow from horizontal, the right would be <Scos(b+pi+a) , Ssin(b+pi+a)> and the left <Scos(b+pi-a) , Ssin(b+pi-a)>. C, then is V_AB + V_left and D is V_AB + V_right.
Sep
27
comment Combinatorics - Building strings with symbols from two alphabets
Welcome to math.SE! If this is a homework question, please tag it as such. Additionally, the community may be more willing to help if you provide some context for the question and show your work up to the point you get stuck - it's easier to teach you how to do the problem than give you the answer.
Sep
27
revised Economics formula
Typeset, tag
Sep
27
suggested approved edit on Economics formula
Sep
26
awarded  Organizer
Sep
26
revised What is the probability of getting 3 aces, a king and a queen
latexify + tags
Sep
26
suggested approved edit on What is the probability of getting 3 aces, a king and a queen
Sep
25
comment Multiplying exponents by fractional exponents and whole numbers to the power of fractional exponents
Why are you dividing the exponent by 2?