If z=3−5i, find |z|.
1 answer:
Answer:
Step-by-step explanation:
The absolute value of z is the distance between the point graphed from the complex number and the origin on a complex plane. In a complex plane, the x axis is replaced by R, real numbers, and the y axis is replaced by i, the complex part of the complex number. Our real number is positive 3 and the complex number is -5, so we go to the right 3 and then down 5 and make a point. Connect that point to the origin and then connect the point to the x axis at 3 to construct a right triangle that has a base of 3 and a length of -5. To find the distance of the point to the origin is to find the length of the hypotenuse of that right triangle using Pythagorean's Theorem. Therefore:
and
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Answer:
11.4
20/100 = x/57
Step-by-step explanation:
It is perhaps simplest just to translate the given English sentence into a mathematical sentence.
... 20% ... ... of ... 57 ... is ... what number
... 20/100 ... × ... 57 .... = ... what number . . . . . . . . translation to math sentence
... 11.4 = what number . . . . . . . . carry out the multiplication
_____
If you're asked to write this as a proportion, you can write it like this:
You can solve this proportion by multiplying by 57 (the denominator under "what number"). Doing so gives you the same arithmetic sentence as shown above.
Answer:
The amount of oil was decreasing at 69300 barrels, yearly
Step-by-step explanation:
Given
Required
At what rate did oil decrease when 600000 barrels remain
To do this, we make use of the following notations
t = Time
A = Amount left in the well
So:
Where k represents the constant of proportionality
Multiply both sides by dt/A
Integrate both sides
Make A, the subject
i.e. At initial
So, we have:
Substitute in
To solve for k;
i.e.
So:
Divide both sides by 1000000
Take natural logarithm (ln) of both sides
Solve for k
Recall that:
Where
= Rate
So, when
The rate is:
<em>Hence, the amount of oil was decreasing at 69300 barrels, yearly</em>