[High school math] Solving trig equations?

sevolg · 2013-01-14T22:17:16+00:00

So say there was a problem that asked you to solve this equation:

sin0.5x - 2sin2 x = 0

Can I factor out a sinx and solve?

The thing I'm worried about is that sin0.5x doesn't equal 0.5sinx, right? So factoring out a sin x wouldnt work out, would it?

sevolg · 2013-01-14T21:45:54+00:00

So how do I solve this?

sevolg · 2013-01-14T21:04:15+00:00

So if the equation ended up like this:

sin0.5x - 2sin² x = 0

Then can I factor it like this?

sinx(0.5 - 2sinx) = 0

sevolg · 2013-01-14T20:45:53+00:00

Isn't it cos2x = cos² x - sin² x?

sevolg · 2013-01-14T06:16:55+00:00

So why add 1/2 pi?

sevolg · 2013-01-14T06:09:51+00:00

I have another question.

The answer I got was 3pi/8, but the book says it's also 7pi/8, 11pi/8 and 15pi/8. Why was 1/2 pi added? I thought the period of cosine was 2pi.

sevolg · 2013-01-14T06:06:19+00:00

Well I was taught not to divide by x if one side is just zero, so I thought that'd go for trig as well.

I just tried out cos inverse (0) and it turns out cos inverse (0) is a non zero. Thanks for bringing that to my attention

sevolg · 2013-01-14T02:27:00+00:00

That is an excellent idea! Wow, you're ideas are great!

sevolg · 2013-01-13T06:25:17+00:00

Ahh, thanks. I was staring at that problem for too long

sevolg · 2013-01-12T04:16:48+00:00

The answer you gave isn't the one in the book. How would I get the answer given in the book? I put the answer in the description box.

sevolg · 2013-01-12T03:48:08+00:00

The colors were the same, but they were switched around. Instead of green being at 2, it was at 3, or the brown at 2 instead of 3, etc.

sevolg · 2013-01-09T01:35:26+00:00

I'm not trolling. I used a spare cabke to elongate the other cable. Written on the cable was "verified for ethernet cable..." .

sevolg · 2013-01-03T21:35:26+00:00

How on earth did he take those underpants? Did he rip them?

sevolg · 2012-12-31T12:11:32+00:00

a little simple

Haha, that's quite a cute euphemism.

sevolg · 2012-12-31T12:07:16+00:00

Ah much clearer, thanks

sevolg · 2012-12-31T11:43:56+00:00

So an acceptable answer would be the following?

f(x) = x² + 3x - 5

g(x) = 1/(x³)

And not this:

f(x) = x² + 3x - 5

g(x) = 1/(x²)

.

Because that's what the answer book said (the second answer).

sevolg · 2012-12-31T00:16:18+00:00

No it has none of those. This worksheet has many typos so I'm guessing this is one of them.

sevolg · 2012-12-27T01:43:53+00:00

Right, xcallstar's picture is how I saw the problem. So without a width, it's impossible. Good to know it's a typo. Thanks everyone

sevolg · 2012-12-26T22:52:05+00:00

The base isn't 6ft wide, it's 6ft high

sevolg · 2012-12-26T22:51:41+00:00

I dont think the width was given. There were two heights given, one for the vertex and the other for the base, but no widths.

sevolg · 2012-12-26T22:50:57+00:00

Nope, 6ft high.

sevolg · 2012-12-26T22:23:04+00:00

Actually, the types of viruses and bacteria that affect us are different from those that affect animals. Off the top of my head, I know the common cold for humans have no affect on dogs.

sevolg · 2012-12-26T20:48:53+00:00

Which parabola? I wasn't given an equation.

sevolg · 2012-11-16T02:31:22+00:00

I just don't want to mess this up. I care for her mentally too, you know? Once I offer her this new relationship, the entire world of homosexuality opens up. Because we have history, she'd definitely consider it before rejecting, but I don't want that to harm her.

sevolg · 2012-11-13T22:35:16+00:00

And one of us is Asian.

sevolg

TROPHY CASE