ddocm

15 Questions
3 Answers

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362

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Dice probability question

Omar has four fair standard six-sided dice. Omar invented a game where he rolls his four dice over and over again until the number 1 does not appear on the top face of any of the dice. Omar wins the game if on that roll the top faces of his dice show at read more ..

ddocm Aug 18, 2021

0

371

1

+69

sequence question

A sequence is defined by a1 = 1 and an = a 2 n−1 + 1 for all n ≥ 2. Find the units digit of a1000

ddocm Aug 18, 2021

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587

2

+69

Graphing circle question

A circle with a radius of 2 units has its center at (0, 0). A circle with a radius of 7 units has its center at (15, 0). A line tangent to both circles intersects the x-axis at (x, 0) to the right of the origin. What is the value of x?

ddocm Mar 7, 2021

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469

1

+69

Algebraic cube question

Six positive integers are written on the faces of a cube. Each vertex is labeled with the product of the three numbers on the faces adjacent to the vertex. If the sum of the numbers on the vertices is equal to 1001, then what is the sum of the numbers read more ..

ddocm Feb 27, 2021

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533

3

+69

Good online math courses?

Does anyone here know any good online math courses? I want something that covers topics in-depth and that is around highschool level in terms of difficulty. I want it to video-based and would rather it be live than pre-recorded. I know this isn't what usually read more ..

ddocm Feb 27, 2021

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490

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+69

Function problem

If f(x)= (ax+b)/(cx+d), abcd ≠ 0 and f(f(x))=x for all x in the domain of f, what is the value of a+d?

ddocm Feb 20, 2021

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426

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Function problem

Let N,O be functions such that N(x) = 2/sqrt(x), and O(x) = x^2. What is N(O(N(O(N(O(3)))))?

ddocm Feb 20, 2021

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538

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+69

Compute the sum (a +(2n+1)d)^2- (a + (2n)d)^2 +(a + (2n-1)d)^2 - (a+(2n-2)d)^2 + ... + (a+d)^2 - a^2

Compute the sum (a +(2n+1)d)^2- (a + (2n)d)^2 +(a + (2n-1)d)^2 - (a+(2n-2)d)^2 + ... + (a+d)^2 - a^2

A full explanation on how to do the problem would be appreciated.

ddocm Feb 14, 2021

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763

4

+69

Power of a point circle question

In the diagram below, EU = 8, UF = 7,GV = 5, VH = 16, and UV= 6. Find XY.

ddocm Feb 3, 2021

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708

3

+69

Semicircle problem

In the adjoining figure, CD is the diameter of a semicircle with center O. Point A lies on the extension of DC past C; point E lies on the semicircle, and B is the point of intersection (distinct from E) of line segment AE with read more ..

ddocm Jan 29, 2021

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785

3

+69

Circle in a trapezoid problem

Quadrilateral ABCD is an isosceles trapezoid, with bases AB and CD. A circle is inscribed in the trapezoid, as shown below. (In other words, the circle is tangent to all the sides of the trapezoid.) The length of base AB is 2x and read more ..

ddocm Jan 28, 2021

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446

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+69

weird function problem

If f(x)= -1/x , what is f(f(f(f(f(6)))))?

ddocm Jan 22, 2021

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523

1

+69

Given that f(x)= (1/ 𝝅 ) x , what is the range of f(x) on the interval [0,∞) ?

Given that f(x)= (1/𝝅)x, what is the range of f(x) on the interval [0,∞)?

Give your answer in interval notation.

ddocm Jan 22, 2021

+1

549

2

+69

Three circles inside of a triangle- geometry

Three circles are drawn, so that each circle is externally tangent to the other two circles. Each circle has a radius of 2. A triangle is then constructed, such that each side of the triangle is tangent to two circles, as shown below. Find the perimeter read more ..

ddocm Jan 21, 2021

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556

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+69

Trapezoid proof problem

Quadrilateral ABCD is an isosceles trapezoid, with bases AB and CD. A circle is inscribed in the trapezoid, as shown below. (In other words, the circle is tangent to all the sides of the trapezoid.) The length of base AB is 2x and the length of read more ..

ddocm Jan 21, 2021

+69

+1

thanks!

ddocmMar 7, 2021

+69

+3

Yes this is correct. Thank you.

ddocmFeb 3, 2021

+69

+1

The answer is wrong. GV * VH = XV * VY isn't true.

ddocmFeb 3, 2021