tan-1 (1/7) + tan-1 (1/13) =
tan-1(1/9)
tan-1 (20)
tan-1(2/9)
tan-1(3/4)
The product s(s-a) (s-b) (s-c) is equal to
Δ
Δ2
2 Δ
Δ/s
Cos (tan-1 3/4) =
4/5
2/5
1/4
3/4
The principal value of sin-1 (1/2)
π
π/2
π/6
0
Sin (1/2 cos-1 4/5)
tan (735o) = tan (2 × 360o + 15o)
Sin 35o
Cos 15o
tan 15o
cot 15o
The value of is
2
1
√2
Area of Δ ABC is
1/2 ab cos C
1/2 ab sin c
1/2 ab cos B
1/2 ca sin B
3
cos 15o =
