# Tutor profile: Earl G.

## Questions

### Subject: Calculus

Find the derivative of x^3.

To find the derivative of x^3, we work in reverse of the integral. Step 1: Write out our equation in integral terms: x^3 / dx = dx / dx - dx is the missing x that is removed in the derivative form of our answer Step 2: In this case we must remove an x from the exponent when taking the derivate. Therefore: x^3 becomes x^2. Step 3: When subtracting the exponent, we must also move the exponent down as a constant. In this case: x^3 moves the 3 to a constant so we get 3x^2 with the x^2 coming from the previous step. Therefore, the derivative of x^3 is 3x^2.

### Subject: Electrical Engineering

If the voltage of a circuit is 10 V, and the resistance is 5 ohms, what is the current of the circuit?

To solve, we use Ohm's Law which is: Voltage = Resistance*Current (represented by I) Therefore plugging in our numbers we get: 10 V = 5 ohms * I Now we solve for I: I = 10 V / 5 ohms This gives us: I = 2 amps

### Subject: Algebra

x^2 + 4 = 20 Solve for x?

Step 1: First isolate the x. x^2 + 4 = 20, subtract 4 from both sides of the equals sign to get x^2 +4 - 4 = 20 - 4 or x^2 = 16 Step 2: Eliminate the exponent. x^2 = 16, now we take the square root of both sides of the equals sign to get square root(x^2) = square root(16) or x = 4 Therefore, x = 4 is our answer.

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