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Deffense [45]
3 years ago
13

Evaluate 6²-7²+8²-9²+..+998²-999²​

Mathematics
1 answer:
Llana [10]3 years ago
3 0

Answer:

-499,485.

Step-by-step explanation:

We can transform this to an arithmetic series by  working it out in pairs:

6^2 - 7^2 = (6-7)(6+7) = -13

8^2 - 9^2 = (8-9)*8+9) = -17  

10^2 - 11^2 = -1 * 21 = -21 and so on

The common difference is -4.

The number of terms in this series  is (998 - 6) / 2 + 1

= 992/2 + 1 = 497.

Sum of n terms of an A.S:

= n/2 [2a1 + (n - 1)d  

Here a1 = -13, n = 497, d = -4:

Sum = (497/2)[-26 - 4(497-1)]

= 497/2 * -2010

= -499,485.

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Nitella [24]
You would use B to find X
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3 years ago
Prove that an = 4^n + 2(-1)^nis the solution to
olga nikolaevna [1]

Answer:

See proof below

Step-by-step explanation:

We have to verify that if we substitute a_n=4^n+2(-1)^n in the equation a_n=3a_{n-1}+4a_{n-2} the equality is true.

Let's substitute first in the right hand side:

3a_{n-1}+4a_{n-2}=3(4^{n-1}+2(-1)^{n-1})+4(4^{n-2}+2(-1)^{n-2})

Now we use the distributive laws. Also, note that (-1)^{n-1}=\frac{1}{-1}(-1)^n=(-1)(-1)^{n} (this also works when the power is n-2).

=3(4^{n-1})+6(-1)^{n-1}+4(4^{n-2})+8(-1)^{n-2}

=3(4^{n-1})+(-1)(6)(-1)^{n}+4^{n-1}+(-1)^2(8)(-1)^{n}

=4(4^{n-1})-6(-1)^{n}+8(-1)^{n}=4^n+2(-1)^n=a_n

then the sequence solves the recurrence relation.

4 0
3 years ago
The interior angles formed by the sides of a quadrilateral have measures that sum to 360°.
stira [4]
The answer is 90 because 360/4 (since it is a quadrilateral) is 90 degrees
5 0
2 years ago
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I need help plssss<br> -3(2x-11)_&gt;8x-9
Ilia_Sergeevich [38]

The Linear inequality holds true for 21 ≥ x;

What is Linear Inequality?

The mathematical expression with unequal sides is known as inequality in mathematics. Inequality is referred to in mathematics when a relationship results in a non-equal comparison between two expressions or two numbers. In this instance, any of the inequality symbols, such as greater than symbol (>), less than symbol (), greater than or equal to a symbol (), less than or equal to a symbol (), or not equal to a symbol (), is used in place of the equal sign "=" in the expression. Polynomial inequality, rational inequality, and absolute value inequality are the various types of inequalities that can exist in mathematics. The symbols "" and ">" signify tight inequalities, while "" and "" signify slack inequalities.

In the given question, the given inequality given is:

-3(2x-11) ≥ 8x-9;

Solving the Inequality:

⇒-6x + 33 ≥ 8x - 9;

⇒33 + 9 ≥ 8x - 6x;

⇒ 42 ≥ 2x;

⇒ 21 ≥ x;

Hence,

The Linear inequality holds true for 21 ≥ x;

To learn more about Linear Inequality, visit:

brainly.com/question/24372553

#SPJ1

4 0
1 year ago
Factors for x squared plus 9x plus 18
Lady_Fox [76]
It is 3-6
So (x+6)(x+3) because 6*3=18 and 6+3=9
3 0
3 years ago
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