r/askmath

The height of Ashley’s problem seems right intuitively, if the parallelogram is pulled down, and the base of Tay’s seems right, but I’m not entirely sure if the units squared is 12. What is the best approach to this problem?

My answer 1. Inf 2. -inf 3.DNE 4. -1 5. DNE

I have tried multiple times but it keeps on saying at least 1 answer is not correct. I don't quite understand why it is incorrect. Please if anyone could help me out on this question, I will be very much appreciated 🙏🏻

Hello, I’ve been struggling with these word problems. If anyone can, is there a possibility that you could explain it with a diagram, I have a test tomorrow and I can’t grasp the diagram part of this unit. Thank you!

they asked me for help, and i said i could try, but they are ahead of me in maths. i have NEVER seen math like this, and they are extremely confused on what theyre supposed to do. they think the end result is supposed to be a letter (i agree), but aren't sure. theyve checked both their textbook and khan academy, but to no avail. they say it is called "integrated math 1". is it possible for just a quick explanation so i can help them out? (they don't have reddit, and i apologize if this kind of post breaks a rule, i js really want to help them ^^)

EDIT: ok so it turns out im just an idiot, i have seen these maths before just not in this format.. oops.. thank you for all your help!!

sé que algunos de ustedes cursáis universidad y veréis esto como una pregunta estúpida, yo voy a noveno grado y por favor necesito ayuda. simplemente copié el resultado de la pizarra

hii help plss, how do i solve this? volume and length. And is the answer same with the stairs form and if it is transformed as a rectangular one? I've tried getting the areas of each steps and now I'm stuck

How you people study math?

I'm a self study person and would like to hear some suggestions from people who are doing math professionally.

This is how I study.

I usually study the theory part first and try to understand the core concepts and stuff like that and go for the examples and try them all of my own. Most of the time I come to the answer atleast have a idea how to initiate or set up.

But some time I'll have zero idea even after seeing the result that why they start that answer like that to prove something (it is this fact that I'm not able to start a proof by myself is exactly what bothers me each time) It seems they picked it out of blue and never in a million year I'll start with this argument because I don't see why they start with that idea at first place(I attached example below).Then I start to question that is my theory part even good? Do i really understood it? etc. All these just because I don't exactly see/know how to start a proof.

For eg take the one I showed in the pic. I will never start the procedure of taking BC× on both sides even if I give my self a whole day to prove that result.

Is this how people usually study or I'm Missing some core understanding or something?

It really frustrates me.

TIA :)

I want to improve my understanding and skills in math due to disabilities. I was recommended to try the textbook Calculus by Robert T. Smith and Roland B. Minton. Currently I am stumped on these three problems from section 2: Derivatives. I would also appreciate advice on how to answer correctly for problems 13 and 17 (like what to include how I got my answer to show my work, not just the sketch). The concept of problems 13 and 17 I really am not understanding and the book and videos I’ve watched have not been the most helpful (as I have a hard time applying what is covered in these resources but struggle with using it for problems not labeled with polynomials or numbers) the closest to explain it has been Curve Sketching by The Infinite Looper on YouTube.

Problem 35 a. Find all the points at which the slope of the tangent line to y = x^3 + 3x + 1 equals 5. The textbook has the answer as (√(⅔), 5 √(⅔) +1), (-√(⅔), -5 √(⅔) +1) and I can not figure out how to get it.

M tan = lim h->0 f(x+h)-f(x)/h

= lim h->0 [(x+h)^3 + 3(x+h) +1)] - [x^3 + 3x +1]/h

= lim h->0 x^3 +3x^2h + 3xh^2 + h^3 +3x + 3h + 1 -x^3 -3x -1/h

= lim h->0 3x^2h + 3xh^2 + h^3 +3h/h

= lim h->0 h(3x^2 +3xh +h^2 +3)/h

= lim h->0 3x^2 + 3xh +h^2 + 3

= 3x^2 + 3x(0) + (0)^2 + 3

= 3x^2 + 3

3x^2 + 3 = 5

3x^⅔ = ⅔

√(x^2) = √(⅔)

X = √(⅔)

And 3(√(⅔)^2 + 3 = 5

Problem 13. Use the graph of f to sketch a graph of f’. (Second picture)

(a)

For x < 0, f is decreasing, so f’ < 0

For x = 0, f has a horizontal tangent line (min), so f’ = 0

For x > 0, f is increasing, so f’ > 0

My graph is the third picture.

(b)

For x < a, f is increasing, so f’ > 0

For x = a, f has a horizontal tangent line (max), so f’ = 0

For a < x < b, f is decreasing, so f’ < 0

For x = b, f has a horizontal tangent line (min), so f’ = 0

For x > b, f is increasing, so f’ > 0

My graph is the fourth picture.

Problem 17. Use the given graph of f’ to sketch a plausible graph of a continuous function f. (fifth picture)

(a)

For x < a , f’ is positive, so f is increasing

For x = a, f’ changes positive to negative, so f has a max there

For a < x < b, f’ is negative, so f is decreasing

For x = b, f’ has a horizontal tangent line (min), so f ?

For b < x < c, f’ is negative, so f is decreasing

For x = c, f’ has a horizontal tangent line, so f ?

For x > c, f’ is negative, so f is decreasing

Once I understand better, I will make the graph.

Thank you for your assistance.

for context, this was a quiz problem and the quiz was handed back to me. in my head, since <ABD is 90 deg. that means DBC also is 90 deg. since ABC is a straight angle. I AM AWARE I MADE MANY INHERENT mistakes such as saying DBH equals 42, etc. could someone please explain this to me so I'm prepared for something like this on our test in a few days?

With the fact that e is not centered idk what do do. I guess i should find a way to locate e in ralotion to the center? DEB should be the same as AEC since they cross eachother. Im just really lost

With 5 is it just 50? Since thats the anlgue that mn cover. 9r does that just apply when its in the circle

All this execrcises seem to be like very simple but i jist dont know T_T

I found this question, the way i solved it was quite long but correct, i solved it by comparing the areas to find the radius. I was hoping if someone could find an easier method. (Calculator isn’t allowed)
The statement and question is written in the pic.

I was solving mean deviation for median but when solving median I came that

20 + 110/14 is 27.86 (AI said) but when I calculate it is 27.85 not 27.86 i asked ai to recheck it but he said “27.86 is correct when rounding the final answer to two decimal places.” is that correct? Or it's ok to write 27.85 exam?