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-   -   Can you help me answer following mathematical questions? (http://mymathforum.com/algebra/345514-can-you-help-me-answer-following-mathematical-questions.html)

Hellov December 22nd, 2018 06:07 PM

Can you help me answer following mathematical questions?
 
Let f(w) = 2w^3 - 5. What is f(4)?

Let f(w) = 2w^3 - 5. Let z = 2. What is f(z)?

Let g(x) = cos(x/2) - 3x. Let f(x) = 2x + 5. What is g(f(x))?

Let f(x) = tan(x) - 2/x. Let g(x) = x^2 + 8. What is f(x)*g(y)?

What is the derivative of x^2 - x + 3 at the point x = 5?

What is the value of x where x^2 - x + 3 is a minimum?

In Python, what is returned when evaluating [n for n in range(10) if n % 2]?

In Python, what kind of error is returned by the following code? (e.g. NameError, ValueError, IOError, etc.) def my_func(n1, n2): return n1 + n2 my_func(1, 2, 3)

What is returned by datetime(1970, 1, 1).strftime('%Y-%d-%B') in Python?

Maschke December 22nd, 2018 06:13 PM

Quote:

Originally Posted by Hellov (Post 603589)
Let f(w) = 2w^3 - 5. What is f(4)?

What are your thoughts? Do you understand what they're asking?

Hellov December 22nd, 2018 06:40 PM

Quote:

Originally Posted by maschke (Post 603591)
what are your thoughts? Do you understand what they're asking?

1019

Maschke December 22nd, 2018 07:40 PM

Quote:

Originally Posted by Hellov (Post 603593)
1019

That's not what I get. I asked if you understand exactly what they're asking. Perhaps you are not understanding the notation. Do you understand what they mean by f(4)?

Hellov December 22nd, 2018 07:53 PM

Quote:

Originally Posted by Maschke (Post 603595)
That's not what I get. I asked if you understand exactly what they're asking. Perhaps you are not understanding the notation. Do you understand what they mean by f(4)?

Oh, I think I made a mistake...

I used 8 instead of 4.

But I was supposed to do
2 x 4x4x4 - 5 = 123 correct?

Maschke December 22nd, 2018 11:11 PM

Quote:

Originally Posted by Hellov (Post 603597)
Oh, I think I made a mistake...

I used 8 instead of 4.

But I was supposed to do
2 x 4x4x4 - 5 = 123 correct?

Yes, good. Can you do the second one? This is a pretty mixed bag of questions. Which one(s) are you having trouble with?

Hellov December 22nd, 2018 11:38 PM

Quote:

Originally Posted by Maschke (Post 603600)
Yes, good. Can you do the second one? This is a pretty mixed bag of questions. Which one(s) are you having trouble with?

I have trouble with all of them...can you just answer them please

topsquark December 23rd, 2018 05:50 AM

Quote:

Originally Posted by Hellov (Post 603601)
I have trouble with all of them...can you just answer them please

No. You are a troll.

-Dan

skipjack December 23rd, 2018 08:50 AM

Quote:

Originally Posted by Hellov (Post 603597)
I was supposed to do
2 x 4x4x4 - 5 = 123 correct?

The next two questions are done similarly.

For z = 2, f(z) = f(2) = 2(2)³ - 5 = 2(8) - 5 = 11.

For f(x) = 2x + 5, g(f(x)) = g(2x + 5) = cos((2x + 5)/2) - 3(2x + 5),
which can be simplified to cos(x + 5/2) - 6x - 15.

In the next question, "*" denotes multiplication.

For f(x) = tan(x) - 2/x and g(x) = x² + 8, f(x)*g(x) = (tan(x) - 2/x)(x² + 8).

The next two questions should have been posted in the calculus forum.

The derivative of x² - x + 3 is 2x - 1. At x = 5, that is 9.

Where x² - x + 3 is a minimum, its derivative is zero, so 2x - 1 = 0.
The required value of x is therefore 1/2.

Your remaining questions, relating to Python, should be posted separately in the Computer Science Forum.


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