in a triangle of ABC, cos^2B+cos^2C-sin^2A-2cosAcosBcosC=0
in a triangle of ABC, cos^2B+cos^2C-sin^2A-2cosAcosBcosC=0
kriti , 9 Years ago
Grade 11
Trigonometry> in a triangle of ABC, cos^2B+cos^2C-sin^2...
2 AnswersAjay
The question does not seem to be correct .
consisder an equilateral traingle wil all angles 60.
Subtituting Cos 60 = ½ and Sin 60 = sqrt3/2 the LHS becomes
¼ + ¼ -3/4 – 2*1/2*1/2*1/2 which is not zero hence it cant be proved.
Ajay
The correct question should be
cos^2B+cos^2C-sin^2A + 2cosAcosBcosC=0 for which proof can be given, but before that please confirm that there is mistake in question
LIVE ONLINE CLASSES
Prepraring for the competition made easy just by live online class.
Full Live Access
Study Material
Live Doubts Solving
Daily Class Assignments
Other Related Questions on trigonometry
In ABC, if cot A+cot B+cot C = cosecA cosecB cosecC, then prove that ABC is right angle triangle.
In ABC, if cot A+cot B+cot C = cosecA cosecB cosecC, then prove that ABC is right angle triangle.
trigonometry
1 Answer Available
Last Activity: 3 Years ago
- Find the general solution of equation tan3∂=cot2∂
For all angles between -720 and +720
- Find the general solution of equation tan3∂=cot2∂
For all angles between -720 and +720
trigonometry
1 Answer Available
Last Activity: 3 Years ago
To prove : Cosec(45 degree - A)Cosec(45 degree + A) = 2SecA
To prove : Cosec(45 degree - A)Cosec(45 degree + A) = 2SecA
trigonometry
1 Answer Available
Last Activity: 3 Years ago
Derive a formula for the area of the triangle, given b, A, B, and C. That is, derive the formula: (b^2sinAsinC)/(2sinB)
Derive a formula for the area of the triangle, given b, A, B, and C. That is, derive the formula: (b^2sinAsinC)/(2sinB)
trigonometry
1 Answer Available
Last Activity: 3 Years ago
WHAT IS THE LIMIT WHEN X TOWARDS TO 0 OF sin6x/5x ? lim𝑥→0 𝑠𝑖𝑛6𝑥/5𝑥
WHAT IS THE LIMIT WHEN X TOWARDS TO 0 OF sin6x/5x ? lim𝑥→0 𝑠𝑖𝑛6𝑥/5𝑥
trigonometry
1 Answer Available
Last Activity: 3 Years ago