Question

In a trianle abc a=4 b=3 angle a=60 degree then c is the root of the equation

Answer 1

answer is (a).using cos rule:a^2=b^2+c^2-2b*c*cosAputting values:16=9+c^2-2*3*c*(.5)we get:c^2-3c-7=a

Answer 2

Answer:

a=4,b=3,∠A=60

0

Using cosine rule,

cosA=

2bc

b

2

+c

2

−a

2

we have

⇒

2

1

=

6c

9+c

2

−16

⇒3c=9+c

2

−16

⇒c

2

−3c−7=0