Show that tan 3x tan 2x tan x = tan 3x – tan 2x – tan x.

Asked by Last Modified  

Follow 1
Answer

Please enter your answer

As an experienced tutor registered on UrbanPro, I can confidently explain how to solve the trigonometric equation you've presented. First off, UrbanPro is indeed a fantastic platform for online coaching and tuition, offering a wide array of subjects and expert tutors. Now, let's delve into...
read more
As an experienced tutor registered on UrbanPro, I can confidently explain how to solve the trigonometric equation you've presented. First off, UrbanPro is indeed a fantastic platform for online coaching and tuition, offering a wide array of subjects and expert tutors. Now, let's delve into the problem at hand: We're tasked with proving the trigonometric identity: tan(3x) * tan(2x) * tan(x) = tan(3x) - tan(2x) - tan(x) To demonstrate this identity, we'll employ some fundamental trigonometric identities and algebraic manipulations: Start with the left side of the equation: tan(3x) * tan(2x) * tan(x) Now, let's express tan(3x) in terms of tan(2x) and tan(x) using the tangent addition formula: tan(3x) = (tan(2x) + tan(x)) / (1 - tan(2x) * tan(x)) Substitute this expression for tan(3x) into the equation: ((tan(2x) + tan(x)) / (1 - tan(2x) * tan(x))) * tan(2x) * tan(x) Expand and simplify: (tan(2x) * tan(2x) * tan(x) + tan(x) * tan(2x) * tan(x)) / (1 - tan(2x) * tan(x)) Rewrite tan(2x) * tan(2x) as tan^2(2x): (tan^2(2x) * tan(x) + tan(x) * tan(2x) * tan(x)) / (1 - tan(2x) * tan(x)) Further simplify: (tan^2(2x) * tan(x) + tan^2(x) * tan(2x)) / (1 - tan(2x) * tan(x)) Now, recall the identity: tan^2(a) = sec^2(a) - 1 Substitute tan^2(2x) and tan^2(x) accordingly: ((sec^2(2x) - 1) * tan(x) + (sec^2(x) - 1) * tan(2x)) / (1 - tan(2x) * tan(x)) Next, utilize the identity: sec(a) = 1 / cos(a) to replace sec^2(2x) and sec^2(x): (((1 / cos(2x))^2 - 1) * tan(x) + ((1 / cos(x))^2 - 1) * tan(2x)) / (1 - tan(2x) * tan(x)) Simplify further: ((1 / cos^2(2x) - 1) * tan(x) + (1 / cos^2(x) - 1) * tan(2x)) / (1 - tan(2x) * tan(x)) Yet again, use the identity: cos^2(a) = 1 - sin^2(a) to rewrite the expressions: (((1 - sin^2(2x)) / cos^2(2x) - 1) * tan(x) + ((1 - sin^2(x)) / cos^2(x) - 1) * tan(2x)) / (1 - tan(2x) * tan(x)) Further simplify: (((cos^2(2x) - sin^2(2x)) / cos^2(2x)) * tan(x) + ((cos^2(x) - sin^2(x)) / cos^2(x)) * tan(2x)) / (1 - tan(2x) * tan(x)) Now, utilize the identities: tan(a) = sin(a) / cos(a) and sin(2a) = 2sin(a)cos(a): (((cos(2x) / sin(2x)) * tan(x) + (cos(x) / sin(x)) * tan(2x)) / (1 - tan(2x) * tan(x)) Simplify the terms involving tangents: ((cos(2x) * tan(x) / sin(2x)) + (cos(x) * tan(2x) / sin(x))) / (1 - tan(2x) * tan(x)) Utilize the identity: tan(a) = sin(a) / cos(a): ((cos(2x) * sin(x) / (sin(2x) * cos(x))) + (cos(x) * (2sin(x)cos(x)) / sin(x))) / (1 - tan(2x) * tan(x)) Now, simplify: ((cos(2x) * sin(x) + 2cos(x)sin^2(x)) / (sin(2x) * cos(x))) / (1 - tan(2x) * tan(x)) Rewrite 2sin(x)cos(x) as sin(2x): ((cos(2x) * sin(x) + sin(2x) * sin(x)) / (sin(2x) * cos(x))) / (1 - tan(2x) * tan(x)) Combine like terms in the numerator: ((cos(2x) * sin(x) + sin(2x) * sin(x)) / (sin(2x) * cos(x))) / (1 - tan(2x) * tan(x)) Utilize the identity: sin(2a) = 2sin(a)cos(a): ((sin(x) * (cos(2x) + sin(2x))) / (sin(2x) * cos(x))) / (1 - tan(2x) * tan(x)) Cancel out sin(x) in the numerator and denominator: ((cos(2x) + sin(2x)) / cos(x)) / (1 - tan(2x) * tan(x)) Now, remember that tan(x) = sin(x) / cos(x): ((cos(2x) + sin(2x)) / cos(x)) / (1 - (sin(2x) / cos(2x)) * (sin(x) / cos(x))) Combine fractions in the denominator: ((cos(2x) + sin(2x)) / cos(x)) / (cos(2x) * cos(x) - sin(2x) * sin(x)) / (cos(2x) * cos(x)) Utilize the identity: cos(2a) = cos^2(a) - sin^2(a) and sin(2a) = 2sin(a)cos(a): ((cos(2x) + sin(2x)) / cos(x)) / ((cos^2(2x) - sin^2(2x)) * cos(x)) Further simplify the denominator: ((cos(2x) + sin(2x)) / cos(x)) / ((cos^2(2x) * cos(x)) - (sin^2(2x) * cos(x))) Rewrite cos^2 read less
Comments

Now ask question in any of the 1000+ Categories, and get Answers from Tutors and Trainers on UrbanPro.com

Ask a Question

Recommended Articles

With the mushrooming of international and private schools, it may seem that the education system of India is healthy. In reality, only 29% of children are sent to the private schools, while the remaining head for government or state funded education. So, to check the reality of Indian education system it is better to look...

Read full article >

E-learning is not just about delivering lessons online. It has a much broader scope that goes beyond manual paper or PowerPoint Presentations. To understand the reach of E-learning and how the whole process works in developing the Educational system, we will discuss a few points here. Let us find out how this new learning...

Read full article >

Learning for every child starts from a very young age. While the formal methods include school curriculums and private lessons, the informal methods include dancing, music, drawing, and various fun-filling activities. Playing games and practising these types of activities helps the children get out of boredom and...

Read full article >

Appearing for exams could be stressful for students. Even though they might have prepared well, they could suffer from anxiety, tension etc. These are not good for their health and mind. However, following a few exam preparation tips can save them from all these and help them to score good marks. Let’s find out all...

Read full article >

Looking for Class 11 Tuition ?

Learn from the Best Tutors on UrbanPro

Are you a Tutor or Training Institute?

Join UrbanPro Today to find students near you