25 Concept List - www.admissionhackers.com/25concepts Parabola Concepts for SAT Math Part 1 - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-_Yst9VbRR7U.htmlsi=GCDaBHCk3W2-egzb Part 2 - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-iQWA5bkI3Fc.htmlsi=NmS8Hit8U1UFyUee 8 Practice Questions - ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-wkLGsN6zeK8.htmlsi=v1kvK96VdH8wGrqW
for circle questions like those, you can also just plug the entire equation into desmos and find out if any of the x values in the choices fall within the circle
Good point. For clarity, as long as the x-coordinate is one of the x-values of the circumference, it will work. Desmos works (and I admit, it's faster) for this question, but it's valuable to learn the equation method for other SAT questions. Thanks for sharing.
@@shlattrtI do too, good luck! If you haven’t figured it out already you can quite literally just type the exact equation into Desmos and it will graph the circle for you. Then from there the question can be a quick process of elimination. If you haven’t practiced using Desmos I highly recommend using some time you have left to check it out.
For the circle question at 0:59, since they're only asking for the X-Coordinate, you could do -4 (X-coordinate of the center) ± 11 (radius, square root of the right side of the equation), and get that the X-Coordinate must be from -15 to 7, which only answer B fulfills.
For the second question, it is also easy to do it by using the concept of sum and product of roots, since the roots of the equation are given in the graph (-3 and 1)
All 3 questions can be done fairly quickly in Desmos although the 3rd is not quite as intuitive. However, the first 2 are very easy and can be done in under 30 secs. No reason to spend 2-4 mins doing all the work by hand esp on #1.
@@NtS785 Yes. Create a table and type in the 3 highlighted points (-2, 6) (-1, 8) (0, -6). Do a quadratic regression y1~ax1^2 + bx1 + c. It will give you values for a, b, c. Type b*c (or just do it in your head).
@@AbdullahKhan-lq1fn Not sure if this is the best way but its how I did it. Use the center point to create circle equation (x+1)^2 + (y-1)^2 = a and add a slider for constant a. Create a table and type in point (5,-4). Using the slider test values for a until the edge of the circle lines up with the point. Do linear equation regression y1=mx1+b. Then I just tested each of the answer choices by adding them to the table to see which one created a tangent.
for the first question (22), it would be much simpler and time-saving to just throw the circle equation into desmos and check for the possible x-intercepts.
For the last question I think using point slope form would be better. If you like only having y on the left then u can simply add over the y1 so u get y = m(x-x1) + y1. It makes it a lot easier bc then u can plug it into desmos as a function without needing to solve for b
For the second question, you can use the sum of roots and product of roots formula. Sum of roots is -b/a, and product of roots is c/a, so you just find the sum of the roots which is -2, and the product of the roots which is -3. Then you plug it into the formula. -b/2 has to equal -2, so b is 4. And c/-2 has to equal -3, so c is 6. Then you just multiply to get your answer of -24.
I enjoyed your solution to the 2nd Problem 7:08 I used Vietta's formula Sum of Roots/Solutions = -b/a Product of Roots = c/a Find c and b and then Multiply I would have used ur method. Wanted to Try this formula out
I want to do good but only two weeks are left ,I haven’t prepped for my exams and I don’t have time and I don’t want to give it more than once I’d love advice from anyone
You can also enter the circle equation into desmos and eyeball it or enter x= -16 which lets you create a slider from -16 to 19 with step 1. Drag the slider around to see which x value actually works. It seems that the digital SAT loves to reinforce that an (x,y) ordered pair satisfies the equation that it is a solution for. Love the way you did the circle question and the way you emphasized the logic. ACT used to include these questions often.
@@jaywestg9248 Your comment is not true. Perhaps you typed the equation wrong. x=-14 perfectly intersects the circle at two points. YT won't allow me to share the desmos link, but if you look up Tutorllini's video about sharing desmos, then you'll know how to access my graph with this info nk42lfi0co
couldnt you see for the circle question if it is inside out outside the range. since the radius is 11, -4+11=7 and -4-11=-15. so 16, 11, and 19 dont work.
1. Create a table with the 2 given points 2. Linear regression on those points: y1~mx1 + b; this gives you the slope of the radius to the point of tangency, m = =-.83333333333 3. Create a new table with 5, -4 4. Linear regression on that new table (the 1 point) with the slope entered as the opp recriprocal of the value from 2 above: y2~(1/.8333333333)x2 + b 5. Look at which points are on the graph or you can type in the points and see if they fall on the line.
I have a video on how to use desmos to do that type of question (linear regression for a line tangent to a circle). It is great that John teaches the fundamentals in case College Board makes some un-Desmosable questions.
Before you start solving the questions, i tried them and I got answers to all of them without even knowing the formulas. With the help of DESMOS i got the answers in 20-40 seconds...
@@shlattrt I typed the equations on the graph and pointed the options on the x-axis like this (-16,0) (-14,0) (11,0) (19,0) and labeled them. then i saw that X-Coordinate must be from -15 to 7 so only -14 can be placed on circle and others are outside of the circle. ngl, I don't remember any formulas but i used my brain and some tricks and Desmos, i got like 700+ in math practice test.
For the second question can you also do it by figuring out the y int from graph for c value and then use a point from the graph say (-2,-6) and then plug it into the equation provided for the b value and then multiply it together(b and c)?
for the last q, couldn't you have just used the inverse of slope from the centre of the circle to the point of tangent instead of finding the entire line ? as both the point of tangent and the new point would need to have the same slope ?
Hi John... I took a bluebook practice test yesterday and I got 740 in maths (5 questions incorrect). But when I compared my score with a practice test I had taken earlier, I saw that I had gotten a 780 in that test with the same amount of incorrect answers. What do you think could be the reason for this?
Hello, it’s because the questions on mdoule 1 are worth more than questions on module 2, of you have before gotten 2 questions wrong on module 2 it will result in 800-2(10)= 780 but now maybe you have got 2 questions wrong on module 1 which can result in 800-2(30)= 740 Hope this helps
The test is adaptive. Bomb an easy question, lose more marks. Solve a tough one, win a lot more marks. Some questions do not even carry marks (generally the toughest ones). Bomb those, lose nothing. Try to solve the easiest questions first, and try not to bomb them.
in order to do that question on desmos there is alot of steps that are required like creating a table, its actually easier to just learn that the tangent line is perpendicular to the radius
It's REALLY easy to do in Desmos. It includes one of the top Desmos skill I'd recommend learning. It's called linear regression. Once you know that, you basically know quadratic regressions as well. I have videos on both, but I think it's rude for me to post them here. It's my video on lines tangent to a circle.
Man, your solutions are so confusing. You just need to start solving based on fundamental concepts. And if you do that, then you easily determine where the center of a circumference is - it is at (-4;19), then you know the radius is 11. Then, imagine the circumference centered at (-4;19) with radius 11. The border x coordinates will be at -15 and 7. You immediately throw choices (A), (C), and (D) away. The only (B) is in this domain of [-15, 7]. But if you want to be extra confident, just plug choice (B) into that equation, and you will find out the corresponding "y" value. Your method of solving these types of problems could mislead and take extra time, which is not a good strategy for an SAT framework.
![[August SAT Math] These 3 Questions were JUST added](/img/logo.svg){kind=logo}
