# Tutor profile: Ricky G.

## Questions

### Subject: Calculus

When solving an indefinite integral, what do you add to the end of your answer? Why?

You add a C to the end of your expression because it accounts for a potential constant that may have turned to zero, whenever the derivative of the equation was taken.

### Subject: Calculus

How do you find the concavity of a non-linear equation?

To find the concavity of a graph you need to use the second derivative test. Then you use a sign chart and check the second derivative around the inflection points that you find by setting the second derivative to equal zero. If you find a positive number after checking the answer, you know that it is concave up. If you find a negative number, you know that it is concave down.

### Subject: Algebra

When dealing with systems of equations, how many equations do you need if you have a problem with three unknown variables?

You would need at least three equations. This is based off a general rule that says that you need to have as many equations as you do variables.

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