Question
Mathematics Question on Triangles
Which of the following is true:
A. If a cos A = b cos B, then the triangle is isosceles or right angled.
B. If in a triangle ABC, cos A cos B + sin A sin B sin C =1 then the triangle is isosceles right angled.
C. If the ex-radii r1, r2, r3 of ΔABC are in the HP, then it's sides are not in AP
Choose the correct answer from the options given below :
A
A and B only
B
B and C only
C
B and C only
D
B only
Answer
A and B only
Explanation
Solution
The correct answer is(A): A and B only