Question

Вычислите:1) 4 cos 90° + 2 cos180° - tg180°;2) cos 0° - cos 180° + sin 90°.​

Answer 1

1) 4 cos 90° + 2 cos180° - tg180°=4*0+2*(-1)-0=-2

2)cos 0° - cos 180° + sin 90°=1-(-1)+1=3

Answer 2

To compute the given expressions, let's use the trigonometric identities:

1. Trigonometric identities:

• cos(90°) = 0
• cos(180°) = -1
• tan(180°) = 0

2. Trigonometric identities:

• cos(0°) = 1
• cos(180°) = -1
• sin(90°) = 1

Now, let's substitute the values into the expressions:

1. 4 * cos(90°) + 2 * cos(180°) - tan(180°) = 4 * 0 + 2 * (-1) - 0 = 0 - 2 = -2

2. cos(0°) - cos(180°) + sin(90°) = 1 - (-1) + 1 = 1 + 1 + 1 = 3

Therefore, the computed values are:

1. -2
2. 3