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Precalculus
Precalculus is a mathematical course or a set of courses that act as a foundation for calculus. The two main topics that are included under precalculus are algebra and trigonometry. Precalculus courses can be structured differently depending upon the type of career path chosen by students. For kids who choose to pursue careers in engineering and medicine, the focus is placed on topics like conic sections, Euclidean vectors, and so on. For careers in fields such as finance precalculus courses focus on topics such as matrices and linear algebra.
In this article, we will take an indepth look at how a standard precalculus course is structured along with the topics included and certain associated examples.
1.  What is Precalculus? 
2.  Precalculus Topics 
3.  Precalculus Formula 
4.  Precalculus Cheat Sheet 
5.  Precalculus Applications 
6.  FAQs on Precalculus 
What is Precalculus?
Precalculus courses act as a prerequisite for calculus and cover advanced mathematical concepts based on quantitative reasoning and functions. Schools usually divide precalculus is two categories  algebra and trigonometry. Before kids can learn how to find the derivatives and antiderivatives of functions they need to understand the fundamental concepts of algebraic functions, transcendental functions, complex numbers, and variable expressions. These act as the basis for precalculus.
Precalculus Definition
Precalculus, as the name suggests, includes courses that need to be studied before learning calculus. Most precalculus courses usually focus on algebraic and trigonometric topics rather than direct calculus concepts. However, if students do not have a deepseated knowledge of these topics then differentiating and integrating functions will be a very hard task.
Precalculus Topics
Precalculus helps in preparing for highergrade and collegelevel calculus courses. The various topics covered under precalculus are as follows:
Complex Numbers
A complex number can be defined as a number that contains a real part and an imaginary part. Such a number is of the form x + iy, where iy is the imaginary number.
The topics covered under this course of precalculus are as follows.
Polynomials
A polynomial is an algebraic expression that consists of variables, coefficients, andconstants that are joined using algebraic operations like addition, multiplication, positive exponentiation, etc.
The list of polynomial topics that fall under precalculus are given below:
Trigonometry
Trigonometry relates the sides of a rightangled triangle to its angles using trigonometric ratios.
The precalculus trigonometry topics covered are as follows:
Functions
Functions are binary relations between two sets where every element of the domain is mapped to exactly one element of the codomain.
The precalculus functions topics are given below:
Sequences/Progressions
Arithmetic, harmonic and geometric sequences are the three types of sequences that fall under a precalculus course.
The important topics covered are listed below.
Conic Sections
Under conic sections, students are introduced to different geometrical figures and their properties that will be used in calculus.
The subtopics that are covered under this are mentioned below.
Matrices
A matrix is a rectangular array where data is organized in the form of rows and columns.
The important topics that fall under matrices are as follows:
Vectors
Vectors are elements that exist in the vector space and represent a quantity having both direction and magnitude.
Given below are the important topics.
Precalculus Formula
Precalculus formulas are indirectly used in finding the derivatives and integrals of functions. They also help in simplifying simple as well as complicated problems in precalculus. Some of the important precalculus formulas are given below:
 i^{2} = 1
 (a + ib) + (c + id) = (a + c) + i(b + d)
 (a + ib)  (c + id) = (a  c) + i(b  d)
 (a + ib) × (a  ib) = a^{2} + b^{2}
 (a + b)^{2 }= a^{2 }+ 2ab + b^{2}
 (a  b)^{2 }= a^{2 } 2ab+ b^{2}
 (a + b)(a  b)= a^{2 } b^{2}
 (a + b + c)^{2} = a^{2} + b^{2} + c^{2} + 2ab + 2bc + 2ac
 Pythagoras Theorem: Hypotenuse^{2} = Perpendicular^{2} + Base^{2}
 sin θ = 1 / cose cθ (OR) cosec θ = 1 / si nθ
 cos θ = 1 / sec θ (OR) sec θ = 1 / cos θ
 tan θ = 1 / cot θ (OR) cot θ = 1 / tan θ
 sin (A + B) = sin A cos B + cos A sin B
 sin (A  B) = sin A cos B  cos A sin B
 cos (A + B) = cos A cos B  sin A sin B
 cos (A  B) = cos A cos B + sin A sin B
 sin 2θ = 2 sin θ cos θ
 cos 2θ = 1  2 sin^{2}θ
 a^{m }× a^{n} = a^{m + n}
 a^{m }/ a^{n} = a^{m  n}
 (ab)^{x} = a^{x} b^{x}
 (a^{x})^{y} = a^{xy}
 Sum of n terms in an arithmetic sequence, S_{n }= (n/2) [ 2a + (n  1) d ]
 Sum of 2 terms in an harmonic sequence = 2ab / (a + b)
 Sum of n terms in a geometric sequence, S_{n }= a (r^{n}  1) / (r  1)
Conic Sections Formulas
 Equation of a circle = (x − h)^{2 }+ (y − k)^{2 }= r^{2}, with the center at (h, k)
 Equation of a parabola is: y = a(x  h)^{2} + k or x = a(y  k)^{2} + h
 Equation of a hyperbola: x^{2}/a^{2}  y^{2} / b^{2} = 1
 Equation of an ellipse: x^{2}/a^{2} + y^{2} / b^{2} = 1
 A^{1}A = I, where A^{1} is the inverse matrix of A and I is the identity matrix.
 C = A + B, where c_{ij} = a_{ij} + b_{ij}, where A, B and C are square matrices.
 C = A  B, where c_{ij} = a_{ij}  b_{ij}
 kA = [ka_{ij}], where 'k' is a scalar.
 u + v = (u_{1}+v_{1}, u_{2}+v_{2}, u_{3}+v_{3}), where, u = (u_{1}, u_{2}, u_{3}) and v = (v_{1}, v_{2}, v_{3})
 u  v = (u_{1}v_{1}, u_{2}v_{2}, u_{3}v_{3})
 u = √(u_{1}^{2} + u_{2}^{2} + u_{3}^{2})
Precalculus Cheat Sheet
A precalculus cheat sheet can be very important as it gives a complete overview of various vital concepts before an examination. It helps to streamline the process of studying and preparing for a test. Given below are some important concepts and formulas that cover the scope of precalculus.
Slope  The slope of a line can be defined as the gradient of the line that describes its steepness. y = mx + c is the general equation of a straight line, where m is the slope and c is the yintercept.
Area of a Triangle  Area of a triangle can be defined as the space covered within the boundary of the triangle. The formula to calculate the area of a triangle is \frac{1}{2}\times base\times height.
Sine Function  The sine function can be defined as the ratio of the perpendicular to the hypotenuse of a rightangled triangle. sin θ = P / H.
Cosine Function  The cosine function is the ratio of the base to the hypotenuse. cos θ = B / H.
Tangent Function  Tangent is the ratio of the sine function to the cosine function. tan θ = P / B.
Ellipse  An ellipse is a curve traced by the set of all points in a plane that have a constant sum from two fixed points.
Hyperbola  A hyperbola is a curve traced by the set of all points in a plane that have a constant difference from two fixed points.
Into Functions  A function where at least one element of the domain will not have a preimage in the domain will be known as an into function.
Square Matrix  A square matrix is one in which the number of rows will be equal to the number of columns. The inverse of a matrix can only be determined for square matrices.
Precalculus Applications
Apart from being the foundation for calculus, there are several areas that see the use of various topics that come under precalculus. Some of the applications of precalculus are listed below:
 Medical fields use precalculus to determine the rate of spread of diseases.
 In architecture, precalculus is used to build robust structures and to ensure their stability.
 Precalculus is used in impact testing for cars to prevent accidents on the road.
 In the field of finance, precalculus is used to build predictive mathematical models.
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Important Notes on Precalculus
 Precalculus comprises the study of topics that are required to learn about calculus.
 Algebra and Trigonometry and the two broad categories of topics that fall under precalculus.
 The topics that fall under precalculus do not focus on direct calculus concepts however, they are needed in order to compute the derivatives and antiderivatives of a function.
Precalculus Problems

Example 1: The equation of a circle is given as x^{2} + y^{2} = 49. Using precalculus, find its radius.
Solution: The equation of a circle is given as (x − h)^{2 }+ (y − k)^{2 }= r^{2}.
The given equation can be written as (x − 0)^{2 }+ (y − 0)^{2 }= 7^{2 }where (0, 0) is the center and 7 is the length of the radius.Answer: Radius = 7

Example 2: If set A = {1, 2, 3, 4}, set B = {14, 15, 16, 17, 18} and f = {(1, 18), (2, 14), (3, 17), (4, 15)} then what type of function is f in Precalculus?
Solution: In the given function, A is the domain and B is the codomain. The elements 14, 15, 17, and 18 have a preimage in the domain. However, 16 is not mapped to any element in A. Thus, the given function is an into function.
Answer: f is an into function

Example 3: Find the value of tan θ if the base of a rightangled triangle measures 4 cm and the hypotenuse equals 5 cm.
Solution: Given, B = 4 cm and H = 5 cm.
tan θ = P / B
According to the Pythagoras Theorem,
Hypotenuse^{2} = Perpendicular^{2} + Base^{2}
P = √(H^{2}  B^{2})
P = √(25  16)
P = 3
Using Precalculus formulas, tan θ = 3 / 4.Answer: tan θ = 3 / 4
FAQs on Precalculus
What Would Precalculus Focus On?
Precalculus is a course or a group of courses in mathematical education that is a prerequisite for learning calculus. The coursework focuses on algebra and trigonometry.
What are the Main Topics of Precalculus?
The two broad categories of precalculus are algebra and trigonometry. Further, the subtopics of precalculus are as follows:
 Polynomials
 Conic sections
 Functions
 Matrices
 Vectors
 Series
What are the important Precalculus Formulas?
The important formulas for precalculus are listed below:
 cos (A + B) = cos A cos B  sin A sin B
 (a  b)^{2} = a^{2}  2ab + b^{2}
 (a + b)(a  b)= a^{2}  b^{2}
 (a + ib) × (a  ib) = a^{2} + b^{2}
 Sum of n terms in an arithmetic sequence, S_{n} = (n/2) [ 2a + (n  1) d ]
 Equation of a circle = (x − h)^{2} + (y − k)^{2} = r^{2}, with the center at (h, k)
 Equation of a parabola is: y = a(x  h)^{2} + k or x = a(y  k)^{2} + h
How Hard is Precalculus?
Precalculus is a very vast subject that includes many topics. However, by building crystal clear mathematical concepts and regular revision of topics, precalculus will be like a cakewalk.
What Grade Level is Precalculus?
Precalculus is introduced to students throughout their school careers. However, the advanced precalculus concepts are restricted for higher grades such as 11th and 12th.
Is Precalculus Considered a Calculus Class?
Precalculus includes the set of topics that are required before starting a calculus course. Thus, it cannot be considered a calculus class but it is designed to prepare students for calculus concepts.
What are the Applications of Precalculus?
Precalculus is used in many industries such as finance, engineering, medicine, and architecture to create complex mathematical models. In addition to this, calculus is based on the topics covered under precalculus.
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