Home
Class 11
MATHS
In triangleABC,angleC=2pi/3,then prove t...

In `triangleABC,angleC=2pi/3`,then prove that `cos^2A+cos^2B-cosAcosB=3/4`

Promotional Banner

Similar Questions

Explore conceptually related problems

In triangleABC,A+B+C=pi ,show that cos2A+cos2B+cos2C=-1-4cosAcosBcosC

In triangleABC,A+B+C=pi ,show that cos^2A+cos^2B-cos^2C=1-2sinAsinBcosC

Prove that: cos^2A+cos^2(A+pi/3)+cos^2(A-pi/3)=3/2

If A+B+C=pi , prove that cos 2A +cos 2B +cos 2C=-1-4cos A cos Bcos C.

In triangleABC,A+B+C=pi ,show that cosA+cosB-cosC=4cos(A/2)cos(B/2)sin(C/2)-1

If A+B+C=pi then prove that cos^2 (A/2)+cos^2 (B/2)-cos^2 (C/2)=2cos(A/2)cos(B/2)sin(C/2)

In triangleABC,A+B+C=pi ,show that sinA+sinB+sinC=4cos(A/2)cos(B/2)cos(C /2)

In triangleABC,A+B+C=pi ,show that sin^2( A/2)+sin^2 (B/2)-sin^2 (C/2)=1-2cos(A/2)cos(B/2)sin(C/2)

In triangleABC , if a=18, b=24, c=30 , then cos((A)/(2))=

If A+B+C=pi , then cos 2A+cos 2B+cos 2C=