Mohon bantuannya untuk nomor 1 dan 2 ya terimakasih :)

1) cos a = 7/9 = x/r
y = |/r^2 - x^2
y = |/9^2 - 7^2
y = |/81 - 49
y = |/32
y = 4|/2
Sec a = 1/cos a
= 1/x/r
= r/x
= 9/7
Sec b = 1/cos b
= 1/x/r
= r/x
= 5/4
y = |/r^2 - x^2
= |/5^2 - 4^2
= |/25 - 16
= |/9
= 3
Tan b = y/r
= 3/5
Csc b = 1/sin b
= 1/y/r
= r/y
= 5/3
Maka, Tan a × Tan b - Sec a × Csc b = 4|/2 / 7 × 3/4 - 9/7 × 5/3 = 3|/2 / 7 - 15/7 = 3|/9 / 7 - 15 =
1/7 (3|/2 - 15)

2) Sec a = 1/cos a
= r/x
= 10/8
y = |/r^2 - x^2
= |/10^2 - 8^2
= |/36
= 6
Csc a = 1/sin a
= r/y
= 10/6
Sin b = 1/2 = y/r
x = |/r^2 - y^2
= |/2^2 - 1^1
= |/4 - 1
= |/3
Ctg b = 1/Tan b
= 1/y/x
= x/y
= |/3 / 1
= |/3
Maka, Ctg ^2 b / 6 × Csc a =
(|/3)^2 / 6 × (10/6) =
3/10

3) (Cos 330° × Csc 315°)/Tan 120° = (-1/2×|/2)/-|/3 = ( 1/2|/2)/|/3

4) Sec^2 300°/ 4×sin60°+2×Cos 210° = (2|/3)^2 /4×|/3/2+2×(-1/2) =
12/9 / 2|/3+(-1) = 12/9 × 1/ 2|/-1 = 12/18|/3-9 = 4 / 6|/3 - 3