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iVinArrow [24]
3 years ago
12

Help me prove this trig identity

Mathematics
1 answer:
alexdok [17]3 years ago
3 0
Hello here is a solution:

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If i=√-1 , what is i^2 equal to ?
Alja [10]

Answer:

-1

Step-by-step explanation:

If i = √-1, then i^2 = -1.

5 0
3 years ago
What does a irrational number look like
julia-pushkina [17]

A irrational number is a number that can't be expressed as a ratio of two whole numbers. That's it.

For examples (in increasing order of difficulty)

1 is a rational number because it is 1/1

0.75 is a rational number because it is equal to 3/4

2.333... (infinite number of digits, all equal to three) is rational because it is equal to 7/3.

sqrt(2) is not a rational number. This is not completely trivial to show but there are some relatively simple proofs of this fact. It's been known since the greek.

pi is irrational. This is much more complicated and is a result from 19th century.

As you see, there is absolutely no mention of the digits in the definition or in the proofs I presented.

Now the result that you probably hear about and wanted to remember (slightly incorrectly) is that a number is rational if and only if its decimal expansion is eventually periodic. What does it mean ?

Take, 5/700 and write it in decimal expansion. It is 0.0057142857142857.. As you can see the pattern "571428" is repeating in the the digits. That's what it means to have an eventually periodic decimal expansion. The length of the pattern can be anything, but as long as there is a repeating pattern, the number is rational and vice versa.

As a consequence, sqrt(2) does not have a periodic decimal expansion. So it has an infinite number of digits but moreover, the digits do not form any easy repeating pattern.

5 0
2 years ago
Your hair is
masha68 [24]
Hdydyxyudhdhdhhducunjehdyfydh did
4 0
3 years ago
Write an expression the "difference of eighteen and two"
Bess [88]
(D): 18-2

Aside from its actual definition—“difference” in math terms talks about and/or means to subtract. The difference is the result/answer to a subtraction problem.
3 0
2 years ago
Simplify write in scientific notation 0.5(8x10^5)
Oksi-84 [34.3K]
10 to the 5th power means 5 times zero, place 8 before that and it will be 800000 then multiply with 0.5 it will be 400000. In scientific notation it will be like 4x10 the 5th power.
7 0
3 years ago
Read 2 more answers
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