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# Recent problems solved by 'richard1234'

richard1234 answered: 5385 problems
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 absolute-value/461522: Explain why it is incorrect to say that absolute value is always positive?1 solutions Answer 316501 by richard1234(5390)   on 2011-06-16 00:31:06 (Show Source): You can put this solution on YOUR website!Because the absolute value of 0 is 0, this automatically makes the above statement false.
 Signed-numbers/461435: 456448454/5000 + 93352662/100001 solutions Answer 316440 by richard1234(5390)   on 2011-06-15 17:47:03 (Show Source): You can put this solution on YOUR website!Other tutor subtracted, not added. 456448454/5000 + 93352662/10000 = (2*456448454 + 93352662)/10000 = 100624957/10000 = 100624.57 And I'm not wrong nor am I an idiot, despite your little "thank you" message.
 Finance/461380: Is there such a symbol as an upside down question mark? Used maybe in loans or mortage or interest. And so, what is it used for? Can you provide an example? Thanks, Remi1 solutions Answer 316409 by richard1234(5390)   on 2011-06-15 15:41:53 (Show Source): You can put this solution on YOUR website!Loans can be considered "upside down" but I rarely see upside down question marks used to describe them (you should Google it). The only use I have seen from an upside down question mark is when one is asking a question in Spanish. But yes, there is such a symbol as an upside down question mark.
 Probability-and-statistics/461206: Twenty seven students averaged 70 on their midterm. Could 15 of them score above 90? Explain1 solutions Answer 316403 by richard1234(5390)   on 2011-06-15 15:03:09 (Show Source): You can put this solution on YOUR website!If 27 students averaged 70, then the total score is 27*70 = 1890. If 15 of them score above 90, this total score must be at least 1350. It is possible for the other 12 to score below 540, so 15 of them scoring above 90 is a possibility.
 absolute-value/461342: Solve: |4x + 2| + 6 =0 1 solutions Answer 316402 by richard1234(5390)   on 2011-06-15 15:00:22 (Show Source): You can put this solution on YOUR website!|4x + 2| = -6 Absolute value cannot be negative, so there are no solutions.
 Circles/461357: What is the radius of the circle (x - 1)2 + (y + 1)2 = 12? 1 solutions Answer 316401 by richard1234(5390)   on 2011-06-15 14:59:41 (Show Source): You can put this solution on YOUR website!The 12 corresponds to r^2, so r is equal to or .
 Graphs/461084: I need to create an equation of a nonlinear function. I don't know what this is. Can you please give me an example? Thanks so much. 1 solutions Answer 316316 by richard1234(5390)   on 2011-06-15 00:36:37 (Show Source): You can put this solution on YOUR website!A nonlinear equation is not necessarily something raised to a power; it is simply an equation that is not represented by a line. In addition to polynomial curves, the following functions are non-linear: Trigonometric function f(x) = sin(x) f(x) = tan(x) Logarithmic or exponential function f(x) = ln x Of course there are countless other examples.
 test/460446: m-3 over 2-3 find value that make expression undefined. 1 solutions Answer 316314 by richard1234(5390)   on 2011-06-15 00:30:16 (Show Source): You can put this solution on YOUR website! is defined everywhere.
 real-numbers/461082: Name the property of real numbers illustrated by the equation. -2(x+11)=-2-221 solutions Answer 316312 by richard1234(5390)   on 2011-06-15 00:28:10 (Show Source): You can put this solution on YOUR website!I presume you mean -2x - 22. And it is the distributive property.
 Reduction-of-unit-multipliers/461164: 0.41411 solutions Answer 316311 by richard1234(5390)   on 2011-06-15 00:25:54 (Show Source): You can put this solution on YOUR website!Is that your p-value?
 Pythagorean-theorem/461155: GIVEN A TRIANGLE ABC WHERE THE VALUE OF BC^2 =370 UNITS AC^2 =74 AND AB^2=116 CALCULATE THE AREA OF A TRIANGLE / HINT; 370=9^2+17^2,74 = 5^2+7^2 AND 116 =4^2+10^21 solutions Answer 316310 by richard1234(5390)   on 2011-06-15 00:24:00 (Show Source): You can put this solution on YOUR website!Please refrain from caps lock...it gives the impression you are shouting your question. We could attempt to find one of the angles using the law of cosines, then find the area using two sides and the in-between angle. However, this gets ugly, plus there is a way to take advantage of the "hint." We can plot the triangle on a Cartesian plane instead, such that it satisfies the requirements: We see that, from the Pythagorean theorem, AC^2 = 7^2 + 5^2, etc. To find the area of ABC, create a rectangle with sides parallel to the axes and with diagonal BC: Next, we just subtract off areas from the big triangle. The area (denote by [ABC]) of triangle ABC is: The coordinates are all lattice points, so the areas are easy to evaluate. (square units)
 Square-cubic-other-roots/461154: square root of c^2 = square root of 68...trying to find the length of an unknown side of a triangle using the Pythagorean theorem. I have solved up till this point, but for the life of me I cannot remember how to solve square roots.1 solutions Answer 316306 by richard1234(5390)   on 2011-06-15 00:02:20 (Show Source): You can put this solution on YOUR website!For positive c, Hence, . It helps to simplify to .
 Probability-and-statistics/460331: an even number given that the color is red1 solutions Answer 316303 by richard1234(5390)   on 2011-06-14 23:46:07 (Show Source): You can put this solution on YOUR website!That's not even a complete sentence, let alone a solvable math question.
 Geometry_proofs/460679: segment BD is congruent to segment BE, and segment BC is congruent to segment BA, what the reason be?1 solutions Answer 316302 by richard1234(5390)   on 2011-06-14 23:38:46 (Show Source): You can put this solution on YOUR website!I don't know, I don't have a diagram in front of me so all I see is some random statement that may or may not be true.
 Graphs/461147: How do you graph a function (hyperbola, ellipse, rational etc.) without using a graphing calculator?1 solutions Answer 316301 by richard1234(5390)   on 2011-06-14 23:34:37 (Show Source): You can put this solution on YOUR website!First determine whether the function is a hyperbola or ellipse or step value function or whatever it could be. Then, find any distinguishing points on the function (for a polynomial it could be max. or min values, for a rational function it could be asymptotes, for an ellipse it could be points on the major/minor axes, etc.). If you are graphing a rational function with multiple asymptotes, it helps to know whether the asymptote is reached from the bottom or top (it might help to know how to find limits first). For an ellipse or circle, know the center and radius or axes.
 Polynomials-and-rational-expressions/460219: Essay: Show all work. Find the following quotient: (4x^2 - y^2) / (2x + y)1 solutions Answer 316300 by richard1234(5390)   on 2011-06-14 23:29:57 (Show Source): You can put this solution on YOUR website!Difference of two squares on the top: I think I have already answered this question yesterday or the day before...
 Mixture_Word_Problems/461143: Determine whether the point (1, 8) is a solution of the system 2x + 6y = 50 10x + 0y = 10 by substituting the point into each equation.1 solutions Answer 316299 by richard1234(5390)   on 2011-06-14 23:28:14 (Show Source): You can put this solution on YOUR website!Just substitute x = 1, y = 8. 2(1) + 6(8) = 50 (true) 10(1) + 8(0) = 50 (true) So (1,8) is a solution to the system (also, the only solution).