669.949 should be your result hope it helps and ask me anything you didn’t understand!
The answers are
a) 245314
b) (k2 + k- 72)/2
a)
Let F(n) denotes the sum of first n natural numbers.
F(n) = (n(n+1))/2
9+10+11+12+13+----------------------+700
F(700) - F(8) = (700*701)/2 - (8*9)/2 = 490628/2 = 245314
b)
9+10+11+-------------------k
F(k) - F(8) = (k(k+1))/2 - (8*9)/2 = (k2 + k- 72)/2
Natural numbers are all positive numbers like 1, 2, 3, 4, and so on. They are the numbers you usually count and they continue till infinity.
Learn more about natural numbers here: brainly.com/question/24672369
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Answer:
Step-by-step explanation:
The main identity you need is the double angle one for cosine:
We get
Expand the numerator to apply the identity again:
Finally, make use of the product identity for cosine:
so that ultimately,
Answer:
Step-by-step explanation:
<u>Step 1: Set x to -5
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Answer: