Regina Litman

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2. Study Group
3. Solving basic Trigonometric functions for all values.

I think that the reason it's marked wrong is that the base number (the one to which the integers are added) is, by convention, expected to be in the range of [-3pi/2, 3pi/2] when looking for the ra...

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2. Content Requests and Feedback
3. Where did the Pixar in a box lessons go?

It looks like you are using a language other than English, plus you may also be registered in a location other than the United States. Some of the courses here are not available in all languages an...

1. Общност
2. Content Requests and Feedback
3. Are there any plans to add more Physics quizzes/unit tests?

Yes, I would like to see practice exercises and unit tests added to AP Physics 2. I got the attention of the person who is in charge of Science here on Khan Academy and asked him if this would be d...

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2. Positive Stories and Testimonials
3. My Travels with Khan Academy (Revised)

One more state to add: Missouri (during a layover in the St. Louis Airport)

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2. News and Updates from Khan Academy
3. Update: New and Improved AP® Biology!

@Grover Underwood and anyone else: If you are using the iPad version, on the All Courses page, look in the Science row, which is the second one from the top.You will likely need to swipe this row f...

1. Общност
2. Content Requests and Feedback
3. Why are there no tests on some subject. e.g. Biology

After I posted my first reply, I discovered that Khan Academy is actively adding new material, including exercises/quizzes/tests, to Advanced Placement (AP) Biology. You can read more here: https:/...

1. Общност
2. Content Requests and Feedback
3. Why are there no tests on some subject. e.g. Biology

Tests have come relatively recently to subjects other than Mathematics, including Biology and other Science subjects. I've noticed that High School Biology has the most comprehensive testing setup....

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2. Study Group
3. Function ans Graphs

Take the equation you formed for part 2 and plug in 9.2 (9 2/10 or 9 1/5) for y and then solve for x. It may be easier if you changed 1/2 to 0.5 and worked with the decimal number y = 9.2.

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2. Study Group
3. Question on Co-ordinate geometry

Graph the two inequalities. One thing that I have computed is that the solution set of this system of inequalities lies entirely within an area of the xy-coordinate plane in which x and y are both ...

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2. Study Group
3. Functions and Graphs

To answer the first one, take a look at the numbers that appear for x (min) and y (cm). Do you notice a relationship between the numbers shown for x and y? Here's a clue - I do. I see that every nu...