Answer:
The mass of the object is 2.6 grams
Step-by-step explanation:
The density of an object is the ratio between its mass and its volume
The equation of the is d = 
, where
Let us use this equation to solve the question
∵ An object has a density of 1.3 g/cm³
∴ d = 1.3 g/cm³
∵ Its volume is 2 cm³
∴ V = 2 cm³
→ Substitute them in the equation of the denisty above
∵ 1.3 = 
→ Multiply both sides by 2
∴ 2 × 1.3 = 2 ×
∴ 2.6 = m
∴ The mass of the object is 2.6 grams
Answer:
13.36
Step-by-step explanation:
I will first create a table
X. Y. XY. X²
1. 20. 20. 1
2. 24. 48. 4
3. 35. 105. 9
4. 46. 184. 16
5. 67. 335. 25
6. 80. 480. 36
1. 12. 12. 1
2. 34. 68. 4
3. 34. 102. 9
5. 78. 430. 25
ΣX = 32
ΣY = 430
ΣXY = 1744
ΣX² = 130
n = 10
The formula for regression line is given as :
Y = a + bX
a = intercept
b = slope
The question requires us to find b which is the slope.
b = nΣXY-ΣXΣY/nΣX²-(ΣX)²
= 10x1744-32x430/10x130-(32)²
= 17440-13760/1300-1024
= 3680/276
= 13.36
b = 13.36
Using the dot product:
For any vector x, we have
||x|| = √(x • x)
This means that
||w|| = √(w • w)
… = √((u + z) • (u + z))
… = √((u • u) + (u • z) + (z • u) + (z • z))
… = √(||u||² + 2 (u • z) + ||z||²)
We have
u = ⟨2, 12⟩ ⇒ ||u|| = √(2² + 12²) = 2√37
z = ⟨-7, 5⟩ ⇒ ||z|| = √((-7)² + 5²) = √74
u • z = ⟨2, 12⟩ • ⟨-7, 5⟩ = -14 + 60 = 46
and so
||w|| = √((2√37)² + 2•46 + (√74)²)
… = √(4•37 + 2•46 + 74)
… = √314 ≈ 17.720
Alternatively, without mentioning the dot product,
w = u + z = ⟨2, 12⟩ + ⟨-7, 5⟩ = ⟨-5, 17⟩
and so
||w|| = √((-5)² + 17²) = √314 ≈ 17.720
