# Tutor profile: Robin R.

## Questions

### Subject: Microsoft Excel

How do I apply VLookUp function and are there any limitations?

The excel function VlookUp is used to find the value from an array using a reference value. It's function can be formally defined as 'Looks in the first column of an array and moves across the row to return the value of a cell' Syntax = VLOOKUP(Value you want to look up, range where you want to lookup the value, the column number in the range containing the return value, Exact Match or Approximate Match – indicated as 0/FALSE or 1/TRUE) Limitation - If the array you are using as reference has duplicate values, VLookUp always return the first match. In this case, you might want ensure that there are no duplicate values or in case there are multiple entries of same reference with different values, you may want to create a unique key using 2 or more cells to use as a unique reference.

### Subject: Marketing

Can you explain Bass model for forecasting?

Let's imagine that a firm is launching a new TV with an entirely new technology or an advanced technology. Then, there will be two set of potential customers- 1. Technology lovers who will buy the TV earlier to try the new tech (Let's call them early adopters or innovators) 2. Late adopters who will buy after others have tested and confirmed that the TV is good (Let's call them imitators) The idea is that information flow from innovators to imitators and thus leads to a bell shaped curve of adoption, defined by the Bass Model. The Bass model helps us estimate probability of adoption at a given time T.

### Subject: Algebra

How would you explain laws of exponents?

Exponents follow three rules: 1. When multiplying powers with same base, the powers add up e.g. 2^3 * 2^4 = 2^(3+4) = 2^7 2. When there is power of a power, we multiply the power e.g. (2^3)^2 , In this expression, the outer power is 2, which means the expression inside the parenthesis is repeated twice so, we can write (2^3)^2 as 2^3 * 2^3 = (2*2*2)*(2*2*2) = 2^6 (we added the powers as same base is multiplied) 3. When there is power of an multiplication expression, we attribute the exponent to each term in the expression and then multiply e.g. (2xy)^3 In this expression, the exponent 3 is applicable to all the three terms in parenthesis - 2, x, and y so, (2xy)^3 = 2^3 * x^3 * y^3 = 8x^3y^3

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