Pei-Hsin Lin 林培心 🌸

1. Общност
2. Study Group
3. Inverse Fucntions

STEP 1 For a given f(x), set f(x) = y. STEP 2 Isolate x in terms of y. STEP 3 Set x = f⁻¹(y). Note that this process does not always yield a function. Many rational functions are not invertible. If...

1. Общност
2. Study Group
3. Quadratics (again; please help!)

Hi Bailey, Use the distributive property in reverse here. Factor out the 3 in both terms of the numerator. 3 ÷ 3 = 1. Any number divided by itself equals 1. The simplified result is just all that's...

1. Общност
2. Study Group
3. Need explanation for a math question

If you think about it in terms of money, two debts put together make an even bigger debt. (-3)³ - 4² =-27 - 16 =-27 + (-16) = -43 The answer would be 11 if the problem were slightly different. (3)³...

1. Общност
2. Study Group
3. Arithmetic Sequence

The explicit formula for arithmetic sequences always follows a specific format. The xth term aᵪ is always equal to the first term a₁ plus the common difference d (x - 1) times: aᵪ = a₁ + d(x - 1) I...

1. Общност
2. Study Group
3. decimals to fractions lowest terms.

METHOD 1:  Do the calculation with decimals. Then convert the answer into a fraction. 0.31 - ¼ = 0.31 - 0.25 = 0.06 = 6/100 = 3/50   METHOD 2: Do the calculation with fractions. 0.31 - ¼ =  31/100 ...

1. Общност
2. Study Group
3. imaginary number division

You actually need to multiply by the conjugate on top and bottom; in other words, multiply by (1 - 4i)/(1 - 4i). This is a fancy way to multiply by 1, since any quantity divided by itself = 1. This...

1. Общност
2. Study Group
3. Absolute value equation graphs

In order to graph h(x) = |2x - 3| - |x + 1| first consider the graphs of  f(x) = |2x - 3|, a v-shaped graph with vertex (³/₂,0) f(x) = -2x + 3 for x ≤ ³/₂ and f(x) = 2x - 3 for x ≥ ³/₂ g(x) = |x + ...

1. Общност
2. Content Requests and Feedback
3. Informal request

Learning with Khan Academy is a self-investment. Think about it. Are you worth it? (Yes.) You can stay on target by making and meeting shorter-term goals. Try to increase your Mission Progress by 7...

1. Общност
2. Study Group
3. Inverse Fucntions

Ah, now we're delving into calculus. If f(x) is restricted to the domain (-1,1) and the range (-∞,∞), then f⁻¹(x) is restricted to the domain (-∞,∞) and the range (-1,1). Restriction to the range (...

1. Общност
2. SAT Questions and Feedback
3. Amazing SAT Practice but not enough Question-Specific Material

Hi Matthew, For help with specific problems, just post your question and the Khan Academy community will try to help you. As for the question you have mentioned: Medicine (M) in milligrams is given...