Can you solve this identity?
in Trigonometry Answers by

Your answer

Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:
To avoid this verification in future, please log in or register.

1 Answer

First check the stated identity: let x=π/3: sec(x)tan(x)=2√3; -csc(x)cot(x)=-(2/√3)(1/√3)=-⅔. Therefore the identity is false. So we need to solve this as an equation with at least one solution.

sec(x)tan(x)=tan(x)/cos(x)=sin(x)/cos2(x).

-csc(x)cot(x)=-(1/sin(x))cos(x)/sin(x)=-cos(x)/sin2(x).

sin(x)/cos2(x)=-cos(x)/sin2(x),

sin(x)/cos2(x)+cos(x)/sin2(x)=0,

(sin3(x)+cos3(x))/(sin2(x)cos2(x))=0.

Therefore sin3(x)+cos3(x)=0=(sin(x)+cos(x))(sin2(x)-sin(x)cos(x)+cos2(x)),

(sin(x)+cos(x))(1-sin(x)cos(x))=0.

Therefore sin(x)=-cos(x), tan(x)=-1, x=¾π+2πn, 7π/4+2πn, where n is an integer.

sin(x)cos(x)=½sin(2x), so ½sin(2x)=1, sin(2x)=2 is not a solution because sine cannot exceed 1.

So the solution is x=¾π+2πn, 7π/4+2πn.

by Top Rated User (1.2m points)

Related questions

1 answer
asked Mar 19, 2013 in Trigonometry Answers by anonymous | 1.5k views
2 answers
1 answer
1 answer
1 answer
asked Mar 14, 2019 in Trigonometry Answers by Ojas Raj | 687 views
2 answers
1 answer
asked Oct 27, 2016 in Trigonometry Answers by anonymous | 1.5k views
1 answer
1 answer
Welcome to MathHomeworkAnswers.org, where students, teachers and math enthusiasts can ask and answer any math question. Get help and answers to any math problem including algebra, trigonometry, geometry, calculus, trigonometry, fractions, solving expression, simplifying expressions and more. Get answers to math questions. Help is always 100% free!
87,516 questions
100,279 answers
2,420 comments
732,347 users