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How do you solve trig identities?

Updated: 12/15/2022
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Q: How do you solve trig identities?
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Is there any use besides food for the brain for Trig identities such as professions which use them?

Trig identities are vital in upper level math. Anything involving the unit circle or triangles is completely based in the trig identities. Trig is used in many other fields, such as architecture, where the identities play a huge role.


How do you solve identities on trigonometry?

Unlike equations (or inequalities), identities are always true. It is, therefore, not possible to solve them to obtain values of the variable(s).


How do you solve trigonometry identities?

by proving l.h.s=r.h.s


Can you help me prove math trig identities?

these are the identities i need sinΘcosΘ=cosΘ sec^4Θ-tan^4Θ=sec²Θcsc²Θ (1+sec²Θ)/(1-secΘ)=(cosΘ-1)/(cosΘ)


Are trigonometry and algebra 2 the same?

No, not even close. Though both work with variables in some instances and other mathematical techniques, such as logarithms and algebraic manipulation, algebra is mostly equation solving to get the variables value, though trig has equations, while trig is the study of triangular and circular measurement and using these measurements to solve specific problems. Trig is much about identities, functions and many formulas while algebra is mostly about function and equation manipulation. Still, they are both mathematical disciplines.


What are the ways on how to solve trigonometric equations?

Generalities.A trig equation contains one or many trig functions of the variable arc x. Solving for x means finding the values of the trig arcs x whose trig functions make the equations true.Example of trig equations:sin (x + Pi/3) = 0.75 ; sin 2x + cos x = 1 ; tan x + 2 cot x = 3 ; tan x + cot x = 1.732.sin x + sin 3x = 1. 5 ; sin x + sin 2x + sin 3x = cos x + cos 2x + cos 3x ;The answers, or values of the solution arcs x, are expressed in terms of radians or degrees:x = Pi/3 ; x = 137 deg. ; x = 2Pi/3 + 2k.Pi ; x = - 17. 23 deg. ; x = 360 deg.The Trig Unit CircleIt is a circle with radius R = 1 unity, and with an origin O. This unit circle defines all trig functions of the variable arc x that rotates counterclockwise on it.When the arc AM, with value x, rotates on the unit circle,The horizontal axis OAx defines the trig function f(x) = cos x.The vertical axis OBy defines the trig function f(x) = sin x.The vertical axis AT defines the trig function f(x) = tan x.The horizontal axis BU defines the trig function f(x) = cot xThe trig unit circle will be used as proofs for solving basic trig equations and trig inequalities.The periodic property of all trig functions.All trig functions are periodic meaning they come back to the same values when the arc x completes one period of rotation on the trig unit circle.Examples:The trig functions f(x) = sin x and f(x) = cos x have 2Pi as periodThe trig function f(x) = tan x and f(x) = cot x have Pi as period.Find the arcs whose trig functions are known.You must know how to find the values of the arcs when their trig functions are known. Conversion values are given by calculators or trig tables.Example: After solving, you get cos x = 0.732. Calculators (or trig table) gives x = 42.95 deg.. The Unit Circle will give an infinity of other arcs x that have the same cos value. These values are called extended answers.Example: Get sin x = 0.5. Trig table gives x = Pi/6. The unit circle give an infinity of extended answers.Concept for solving trig equations.To solve a trig equations, transform it into one or many basic trig equations.Basic trig equations.There are 4 of them. They are also called "trig equations in simplest form".sin x = a ; cos x = a (a is a given number)tan x = a ; cot x = aSolving basic trig equations.The solving method proceeds by considering the various positions of the variable arc x, rotating on the trig circle, and by using calculators (or trig tables).Example 1. Solve sin x = 0.866Solution. There are 2 answers given by calculators and the trig circle:x = Pi/3 ; x = 2Pi/3 (answers)x = Pi/3 + 2k.Pi ; x = 2Pi/3 + 2k.Pi (extended answers)Example 2. Solve cos x = 0.5Solution. 2 answers given by the trig table and the trig circle:x = 2Pi/3 ; x = - 2Pi/3 (answers)x = 2Pi/3 + 2k.Pi ; x = -2Pi/3 + 2k.Pi (extended answers)Note. The answer x = - 2Pi/3 can be replaced by x = 2Pi - 2Pi/3 = 4Pi/3.How to transform a given trig equation into basic trig equations.You may use:- common algebraic transformations, such as factoring, common factor, polynomials identities....- definitions and properties of trig functions...- trig identities (the most needed)Common Trig Identities.There are about 31 of them. Among them, the last 14 identities, from #19 to #31, are called "Transformation Identities" since they are necessary tools to transform a given trig equation into many basic ones. See book titled "Solving trig equations and inequalities" (Amazon e-book 2010)Examples of trig identities: sin^2 a + co^2 a = 1 ; sin 2a = 2sin a.cos a ;1 - cos 2a = 2 sin^2 a ; cos a = (1 - t^2)/(1 + t^2)Methods to solve trig equations.There are 2 common methods to solve a trig equation, depending on transformation possibilities.Method 1. Transform it into a product of many basic trig equations, by usingcommon transformation tools or by using trig identities.Example 3. Solve 2cos x + sin 2x = 0.Solution. Replace sin 2x by 2sin x.cos x (Trig Identity #10)2cos x + sin 2x = 2cos x + 2sin x.cos x = 2cos x(1 + sin x).Next, solve the 2 basic trig equations: cos x = 0 and sin x + 1 = 0.Example 4. Solve cos x + cos 2x + cos 3x = 0.Solution. Using trig identity #26, transform it into a product of 2 basic trig equations: cos 2x (2 cos x + 1) = 0. Next, solve the 2 basic trig equations: cos 2x = 0 and cos x = -1/2.Method 2. If the trig equation contains many trig functions, transform it into an equation that contains only one trig function as a variable.Example 5. Solve 3cos ^2 x - 2sin^2 x = 1 - 3sin xTransform the equation into the one containing only sin x. Replace cos^2 x = 1 - sin^2 x (Trig Identity 1). Call sin x = t.3(1 - sin^2 x) - 2sin^2x +3sin x - 1 = 03 - 3t^2 - 2t^2 + 3t - 1 = -5t^2 + 3t + 2 = 0.This is a quadratic equation with 2 real roots 1 and -2/5. Next solve the 2 trig basic equations: sin x = t = 1 and sin x = t = -2/5.The common period of a trig equation.The common period of a given trig equation must equal the least multiple of all the contained trig functions' periods.Example: The equation cos x + tan x = 1 has 2Pi as common period.The equation f(x) = sin 2x + cos x = 0 has 2Pi as common periodThe equation sin x + cos x/2 has 4 Pi as common period.Unless specified, a trig equation must be solved covering at least one common period.Solving special types of trig equations.There are a few special types of trig equations that require specific transformations.Examples: asin x + bcox x = ca(sin x + cos x) +bsin x.cos x = casin^2 x + bsin x.cos x + c cos^2 x = 0.Checking answers.Solving trig equation is a tricky work that easily leads to errors and mistakes. The answers should be carefully checked.After solving, you may check the answers by using graphing calculators. To know how, see the book mentioned above.(This article was written by Nghi H. Nguyen, the co-author of the new Diagonal Sum Method for solving quadratic equations)


Is there an analytical way to solve trig functions?

yes. there are certain formulae for solving them. dont remember


How do you solve trig cut ups?

You have to simplify all of the expressions and then match up the ones that equal eachother.


How do you solve complicated trigonometry questions?

You make them less complicated by using trigonometric relationships and identities, and then solve the less complicated questions.


How can you make good marks in maths calculus?

Know you algebra and trig. When I took calculus that is what my teachers told me. You will use both extensively in manipulations and identities and functions. Then you can learn the calculus.


What are the identities in trigonometry?

In trigonometry, identities are mathematical expressions that are true for all values of the variables involved. Some common trigonometric identities include the Pythagorean identities, the reciprocal identities, the quotient identities, and the double angle identities. These identities are used to simplify trigonometric expressions and solve trigonometric equations.


How do you solve this trig problum?

First, you learn to spell problem. Second, you learn to include the problem when you ask a question on this site.