# Tutor profile: Valeria C.

## Questions

### Subject: Pre-Calculus

Hello! I am having a hard time trying to understand when a trigonometric function is positive or negative in the unit circle. If somebody can help to figure out a dynamic manner to learn it. I would appreciate it!

Hi! The unit circle is divided into four quadrants Top Right (Quadrant I): all trigonometric functions are positive (ALL)-all of them Top Left (Quadrant II): sine and cosecant are positive (STUDENTS)-trigonometric function that starts with "S" and its reciprocal Botton left (Quadrant III): tangent and cotangent are positive (TAKE)-trigonometric function that starts with "T" and its reciprocal Botton Right (Quadrant IV): cosine and secant are positive (CALCULUS)-trigonometric function that starts with "C" and its reciprocal To understand and memorize where the trigonometric functions are positive or negative. We can use a small phrase which is " ALL STUDENTS TAKE CALCULUS" and follow the counterclockwise direction. I hope this helps! :D

### Subject: ACCUPLACER

Hi! I’m having trouble writing out a problem with first degree equations. The problem is written, as follows: write the cube of the double of x and leave your answer as an expression

Hello, first let me define a mathematical expression. An expression is a mathematical phrase that does not contain an equal sign. Once the concept becomes clear, the writing out of the expression gets much easier. The instruction says "write the cube of the double of x". - The first question that should come to our mind is " What is the double of x" Answer: the double of x is simply twice the variable, in this case, the name of the variable s "x", So, the double of x is (2x) - The second question is related to the cube and it should be " what is a cube?" Answer: in this scenario "cube" represents the exponent which will affect the (2x). So, it will be (2x)^3 Overall, the expression can be written as: (2x)^3 Solving the expression, we will get: 8x^3 Note: remember that while the parenthesis is around the (2x) the exponent will affect the number and the variable "x".

### Subject: Algebra

Hello! I have an algebra question. I have to create a system of first-degree equations with three incognitas. Is it possible to solve the system with only two equations? Please, I need an explanation. Thanks!

Hello! It is not possible to solve a system of three incognitas with only two equations. The number of variables (incognitas) indicates the number of equations the system should have to be solved. For example: If I have only two equations in the system. The problem is always going to come with how to find the third variable. It means an equation is missing. x=5+y y+z=3-x Even if the system is solved by substitution, a third equation to solve all the variables and find a numerical value is needed.