Step-by-step explanation:
-13 - 23 = -13 + (-23)
= -36
-13 - (-23) = -13 + 23
= 10
2 sin² x - sin x - 1 = 0
u = sin x ( substitution )
2 u² - u - 1=0
2 u² - 2 u + u - 1 = 0
2 u ( u - 1 ) + ( u - 1 ) = 0
( u - 1 ) + ( 2 u + 1 ) = 0
( sin x - 1 ) ( 2 sin x + 1 ) = 0
sin x - 1 = 0 or: 2 sin x + 1 = 0
sin x = 1 sin x = -1/2
x 1 = π/2 + 2 kπ x 2 = 7π/6 + 2 kπ, x 3 = - π/6 + 2 kπ, k ∈ Z
k ∈ Z
Answer: 5/18
Step-by-step explanation:
Answer:rational
Step-by-step explanation:
1. One face is 5.1*2.5=12.75 un^2, one is 8.5*2.5=21.25, one is 6.8*2.5=17, and two are 1/2*6.8*5.1, so both are 34.68. Total is 85.68, rounded to 85.7 cm^2. (C)
2. The area of the circles is 2(π*2^2), which is about 25.1. The rectangle's area can be found as 2π*2*3, which is about 37.7. The total is rounded to 62.8 m^2 (D)
3. Rectangular faces: 3.6*1.8=6.48, 8.5*1.8=15.3, 7.7*1.8=13.86
Triangles: 2(1/2(3.6*7.7))=27.72
Total: 63.36, round to 63.4 km^2 (B)