In a triangle , ,

MATHEMATICS · Single correct · A Level · Mathematics · Trigonometry · Trigonometry

Problem

In a triangle

ABC

a

b

, and

A

are given, and

c_1

and

c_2

are the two possible values of the third side

c

. The sum of the areas of the two triangles with sides

a,b,c_1

and

a,b,c_2

is (1)

\frac{1}{2}b^2\sin2A

(2)

\frac{1}{2}a^2\sin2A

(3)

b^2\sin2A

(4) None of these