Jawaban:

1) 156,38

2) (4/3) [√2 - 1]

3) √3

4) (4/3)(√3)

Penjelasan dengan langkah-langkah:

1)

Cos A = 7/9

Cos A = Sin A/Tan A = 7/9

artinya: Sin A = 7 Tan A = 9

Sec B = 5/4

Sec B = 1/Cos B = 1/(SinA/TanB) = TanB/SinA = 5/4

artinya Sin A = 4, Cos B = 4/5, Tan B = 5

Tan A.Tan B - Sec A.Cosec B =

9 . 5 - 1/CosA . 1/SinB =

45 - (9/7) . (1/4) = 45 - (9/28) = 156,38

2)

Sec A = 10/8

Sec A = 1/CosA = TanA/SinA = 10/8

artinya Sin A = 8, Cos A = 8/10, Tan A = 10

Sin B = 1/2

Sin B = CosB.TanB = 1/2

Cot²B/6Cosec A = (cosec²B -1)/6CosecA

= [√(1/SinB) - 1 ] / [ 6 (1/SinA)]

= [√2 - 1 ] / [6 (1/8)

=(4/3) [√2 - 1 ]

3)

(Cos 330° x Cosec 315°) / Tan 120° =

= [ Cos (360°- 30°) x Cosec (360° - 45°) ] / (Tan (90° + 30°))

= { Cos (360° - 30°) x 1/[Sin (360° - 45°)] } / (Tan (90° + 30°))

= [ Cos 30° x ( - 1/Sin 45°) ] / ( - Cot 30°)

= (1/2)(√3) x (-2/√2) / - (CoS 30°/Sin 30°)

= (1/2)(√3)(-√2) / - [(1/2)(√3)/(1/2)]

= (-3) / - √3 = √3

4)

Sec²300° / [ (4 Sin 60°) + 2 Cos 210°) ] =

= (Tan²300° + 1) / [ (4(1/2(√3))) + 2 Cos (180° + 30°) ]

= (Tan²(360° - 60°) + 1) / [ (2√3) - 2 Cos 30° ]

= ( - Tan²60° + 1 ) / [ (2√3) - 2 (1/2(√3)) ]

= ( 3 + 1) / (√3) = (4/3)(√3)

Tolong ya kak, jawaban saya dijadikan 'jawaban tercerdas,' karena lama dingetiknya ini, sekalian biar dapet poin misi juga saya, please dan terima kasih :)