1.Tentukan nilai dari Cosec 3Π/4.Sin 2Π/3 2.Diketahui Cos a = 7/25 dan 270°

1.
cosec 3π/4 . sin 2π/3
= cosec 3.180/4 . sin 2.180/3
= cosec 135° . sin 120°
= 1/sin 135° . sin 120°
= √2 . 1/2 √3
= 1/2 √6

2.
cos a = 7/25 = x/r
y² = r² - x²
y² = 25² - 7²
y² = 576
y = 24

a berada di kuadran IV, maka
sin a = y/r = -24/25
tan a = y/x = -24/7
cosec a = r/y = -25/24
sec a = r/x  = 25/7
cotan a = x/y = -7/24

[tex]\text{Cosec} \frac{3 \pi }{4}\,\,\text{x}\,\,\text{Sin} \frac{2 \pi }{3}\\= \text{Cosec 135}\,\,\text{x}\,\,\text{Sin 120}\\ = \sqrt{2}\,\,\text{x}\,\, \frac{ \sqrt{3} }{2}\\= \frac{ \sqrt{6}}{2}\\\\ \text{Cos A = } \frac{7}{25}\\\text{Sin A} = -\frac{24}{25}\\\text{Tan A} = -\frac{24}{7}\\\text{Cosec A = } -\frac{25}{24}\\\text{Secan A =} \frac{25}{7}\\\text{Cotan A =} -\frac{7}{24} [/tex]

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