- #1
- 169
- 0
I know that sin 320 deg is equal to -sin 40 deg. However, how do you know that -sin 40 deg is equal to - cos 50 deg? Thanks
Draw a right triangle and look at the relationships.I know that sin 320 deg is equal to -sin 40 deg. However, how do you know that -sin 40 deg is equal to - cos 50 deg? Thanks
Don't set them equal... you can do a number of things... you can multiply the numerator and denominator by -1... that keeps the fraction the same, and lets you multiply out the (-2x+1) by -1...Ok thanks.
Also, how do you solve this problem?:
[tex]\frac{x^{2}-9x+14}{3x^{3}-6x^{4}} \times \frac{2x-1}{x^{2}-2x-35}[/tex]
I simplified it down to:
[tex] \frac{(x-7)(x-2)}{3x^{3}(-2x+1)} \times \frac{2x-1}{(x-7)(x+5)}[/tex]
Is there a way to cancel out (-2x+1) and 2x-1? Is it okay to multiply (-2x+1) by -1 or is it wrong because it changes the value? When I set them equal to one another they cancel out to equal 0. Why is this?
Thanks.
Thanks for your reply! I didn't even see that you could factor -1 out. Does anyone know the correct definition of Standard Deviation and how to find it? I've searched on google and all that came up were some confusing equations...Don't set them equal... you can do a number of things... you can multiply the numerator and denominator by -1... that keeps the fraction the same, and lets you multiply out the (-2x+1) by -1...
Or multiply the denominator by (-1)*(-1) which is just one so you're keeping the value of the fraction the same... but you can use one of the -1 to multiply (-2x+1) by -1...
The essential idea is that -2x+1 = -1*(2x-1) = -(2x-1). You can also think of it as factoring out the -1.
Remember that whatever operations you do, you don't want to change the value of the quantity you're evaluating...
When you cancel things out with multiplication, you're dividing something by itself... so you don't get 0, but 1...
Okay, I'm nowhere near that level of math so I've found a defintion that I think I can apply. Please tell me if you think this is accurate or not:Yes, u have to use those confusing equations to calculate standard deviation.
http://www.answers.com/topic/standard-deviation?cat=biz-fin#
I liked the one that's in "Accounting Dictionary" section(scroll down to there), and
if you further scroll down, wikipedia explains it all (including that bell curve)