Answer:
as written: 2500.2
as intended: 3000
Step-by-step explanation:
20% = 0.2, so adding 0.2 to 2500 gives 2500.2
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We suspect you want to add 20% of 2500 to 2500. That is ...
2500 + 20%×2500
= 2500 + 0.20×2500
= 2500 + 500
= 3000
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<em>Comment on percentages</em>
A percentage is a pure number. It is a ratio of like quantities, so has no units.* A <em>useful</em> percentage always has a base. That is, it is a percentage <em>of something</em>. Sometimes that base may be unclear or unstated, in which case the percentage might very well be considered to be meaningless.
In any event, a percentage is simply a (unitless) fraction. The "%" symbol means the same thing as "/100", so 20% means 20/100 = 2/10 = 1/5.
The very clear math expression 2500 +20% means simply 2500 + 1/5, which is the mixed number 2500 1/5 or the decimal value 2500.2. Usually, when we want to add a percentage to some value, we want the percentage to be <em>of the original value</em>. When that is written as a math expression, it must show this:
2500 + 20% of 2500
2500 + 20%×2500
2500(1 +20%)
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* The concentration or potency of some medicines or other mixtures may be expressed as a percentage that is the ratio of one unit to a different unit, typically weight per volume. That is, a "0.1%" preparation may be 0.1 grams per 100 mL, for example. You have to read the label to determine whether this is the case. Mathematically, this is not a percentage, but is a non-standard use of the "%" symbol to indicate a ratio to 100 of something.
It would be equal to 4
Hope this helps!
You need to add the dollar sign so it will look like $0.50 or you could put $.50
the reciprocal of 2 and 3/5 is 5/13
Answer:
you're not doing anything wrong
Step-by-step explanation:
In order for cos⁻¹ to be a function, its range must be restricted to [0, π]. The cosine value that is its argument is cos(-4π/3) = -1/2. You have properly identified cos⁻¹(-1/2) to be 2π/3.
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Cos and cos⁻¹ are conceptually inverse functions. Hence, conceptually, cos⁻¹(cos(x)) = x, regardless of the value of x. The expected answer here may be -4π/3.
As we discussed above, that would be incorrect. Cos⁻¹ cannot produce output values in the range [-π, -2π] unless it is specifically defined to do so. That would be an unusual definition of cos⁻¹. Nothing in the problem statement suggests anything other than the usual definition of cos⁻¹ applies.
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This is a good one to discuss with your teacher.