Tentukan nilai dari: a. 2 sin 360 derajat - cos^2 Phi + tan 3 Phi/4 b. 2 cos^2 90 derajat - cot 30 derajat / 4sin^2 30 derajat

Jawab:
a.
2 sin 360° - cos² π + tan 3π/4
= 2 sin 360° - cos² 180° + tan 3.180°/4
= 2 . 0 - [cos 180°]² + tan 540°/4
= 0 - [-1]² + tan 135°
= 0 - 1 + tan [180° - 45°]
= -1 - tan 45°
= -1 - 1
= -2

b. 
2 cos² 90° - cot 30° / 4 sin² 30°
[tex]=\frac{ 2 [cos 90 ^{0}] ^{2}-cot30 ^{0} }{4[sin 30 ^{0}] ^{2 } } \\ = \frac{2[0] ^{2}-cot30 ^{0} }{4[ \frac{1}{2} ] ^{2} } \\ = \frac{0 - cot30^{0}}{4[ \frac{1}{4}] } \\ = \frac{0-cot30 ^{0} }{1} \\ =0- \frac{cos}{sin} 30 ^{0} \\ =0 - cos30 ^{0} \\ = 0 - \frac{1}{2} \sqrt{3 } \\= -\frac{1}{2} \sqrt{3 } [/tex]