Answer:
8.8
Step-by-step explanation:
kids cheating in tests.....
8.7749643787
8.8(1dp)
Answer:
Your expression equals 
assuming the problem was to simplify 
to the form 
.
Step-by-step explanation:
Let's use the following identity: 
which is comparable to the form .
Factorize the quadratic.
We have 
, so
Now, both 
and 
(since the absolute value of any number cannot be negative), so we just need to worry about when the left side is exactly zero. This happens for
So the solution to the inequality is the set
Answer:
a) 1+2+3+4+...+396+397+398+399=79800
b) 1+2+3+4+...+546+547+548+549=150975
c) 2+4+6+8+...+72+74+76+78=1560
Step-by-step explanation:
We know that a summation formula for the first n natural numbers:
1+2+3+...+(n-2)+(n-1)+n=\frac{n(n+1)}{2}
We use the formula, we get
a) 1+2+3+4+...+396+397+398+399=\frac{399·(399+1)}{2}=\frac{399· 400}{2}=399· 200=79800
b) 1+2+3+4+...+546+547+548+549=\frac{549·(549+1)}{2}=\frac{549· 550}{2}=549· 275=150975
c)2+4+6+8+...+72+74+76+78=S / ( :2)
1+2+3+4+...+36+37+38+39=S/2
\frac{39·(39+1)}{2}=S/2
\frac{39·40}{2}=S/2
39·40=S
1560=S
Therefore, we get
2+4+6+8+...+72+74+76+78=1560
Answer:
S = 1564
Step-by-step explanation:
S = 12 + 22 + 32 + .. + 172
= 12 + (12+10) + (12+20) + .. + (12+160)
= 10(1 + 2 + .. + 16) + 12×17
= 10×16×17/2 + 12×17
= 1360 + 204
= 1564
