von luger

1. Community
2. General Khan Academy Questions
3. What is the difference between Biology and High School Biology?

Hi Christine, If you mean to ask what the difference is between the two courses, then the normal Biology course is a lot more thorough and extensive, while the High School Biology course is more se...

1. Community
2. Content Requests and Feedback
3. Request to add content about Einstein's theory of relativity

Hi Dekin, I found a content page for special relativity (https://www.khanacademy.org/science/physics/special-relativity), but not general relativity, as you wanted. Unfortunately, I don't think we ...

1. Community
2. Content Requests and Feedback
3. Request to add content to the Electrical engineering course

I've noticed that Khan Academy's Electrical Engineering section is a bit underdeveloped, and your request is completely understandable. I've escalated your concern about the limited content to high...

1. Community
2. Classroom Tips and Tricks
3. Is there a way to assign a mastery goal of a single unit?

To my knowledge, teachers can only assign mastery goals for the whole course, not for units. However, your idea seems quite helpful; I'll escalate it further so it can be made a future possibility....

1. Community
2. Study Group
3. Sinosoidal Equations help!!

Here's the solution: 7cos(9x) -1 = 1 cos(9x) = 2/7           like you said 9/x = cos^-1(2/7) 9/x = 73.40 x = 9/73.40 x = 0.1226 I used cos^-1 to solve the problem, which you should be able to find ...

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2. Study Group
3. Derivatives of inverse trig functions sec^-1(x) and csc^-1(x)

These videos worked for me, since I don't think that KA has proofs for more advanced trig derivatives like those. Feel free to check these out, and let me know if they help. If not, I can try to fi...

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2. Study Group
3. why is this compund inequality not following the rules of divideing a negative number?

Here's how I would solve this question; that might clear up some confusion.  12x - 39 < 9 12x < 48 x < 4 and  -4x + 3 < -6 -4x < -9 x > (9/4) So, 9/4 < x < 4 If you need any clarification in terms ...

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2. Study Group
3. Request to add Ap chemistry and Neet and aiims exam

The AP Chemistry course on KA can be used to prepare for the AP Chemistry Exam, which is administered by the College Board and is used to gain university credits in many countries, but is most comm...

1. Community
2. Study Group
3. Chiral center example set 2 organic chemistry

Hi Bonnie,  Here's the structure of 1,3-difluorocyclopentane, with one of its chiral carbons notes as the black C. When looking at whether an atom has the four different groups that make it chiral,...

1. Community
2. Study Group
3. Stoichiometry and Limiting Reagent problems

Firstly, it's wrong to use the excess reagent because how much of it will actually be used in the reaction is completely unknown. Using the limiting reagent is necessary, because that is the one th...