if acos^2C/2+ccos^2A/2=3b/2 then show that a,b,c are in a.p.
if acos^2C/2+ccos^2A/2=3b/2 then show that a,b,c are in a.p.
Haimanti , 6 Years ago
Grade 11
Trigonometry> if acos^2C/2+ccos^2A/2=3b/2 then show tha...
1 Answers
Arun
Last Activity: 6 Years ago
we know cosC=2cos^2(C/2)-1
so, a(1+cosC)/2+c(1+cosA)/2=3b/2
a+acosC+c+ccosA=3b
a+c+(acosC+ccosA)=3b
Using By projection formula: (acosC+ccosA)=b
a+c+b=3b
a+c=2b
This shows that a,b,c are in A.P.
Regards
Arun
Provide a better Answer & Earn Cool Goodies
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
Ask a Doubt
Get your questions answered by the expert for free
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: 2 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
0 Answer Available
Last Activity: 2 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
0 Answer Available
Last Activity: 2 Years ago
cos^2 13ºcos^2 47º+cos^2 73º =? …..................
cos^2 13ºcos^2 47º+cos^2 73º =? …..................
trigonometry
0 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
0 Answer Available
Last Activity: 3 Years ago