/sci/ - Science & Math » Thread #9240157

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Trig

Anonymous Wed 18 Oct 04:35:17 2017 No.9240157 View Reply Original Report

Quoted By: >>9240163 >>9240173 >>9240281

Math help.
Trig is kicking me in balls, maybe /sci/ can help me more than khan academy is right now.

Right now I'm working on Analytic Trigonometry
Here are the problems I'm working on. I'd like help understanding them as I have the answer sheet in the back of the book, thanks!

1. cos(20+A)

2. sec x cos (-x) + tan^2x

Numbers 61 and 67 in pic provided.

Links to videos will be helpful, too.

Anonymous

Anonymous Wed 18 Oct 2017 04:42:12 No.9240163 Report

Quoted By: >>9240179

>>9240157
Nobody wants to do your dumbass grade school hw for you fuck right off m8

Anonymous

Anonymous Wed 18 Oct 2017 04:47:38 No.9240173 Report

Quoted By: >>9240174 >>9240179 >>9240395

>>9240157
Read your fucking textbook. Why the fuck do kids not read their goddamn textbooks that literally provide them with examples and show how to do these? Fuck you OP and fuck your 7th grade math homework

Anonymous

Anonymous Wed 18 Oct 2017 04:51:24 No.9240174 Report

Quoted By: >>9240179 >>9240180

>>9240173
Lets be real if you were doing trig in 7th grade you were a turbo autist with no friends

Anonymous

Anonymous Wed 18 Oct 2017 04:53:40 No.9240179 Report

Quoted By:

>>9240163
You're not going to let /b/ be fore helpful than you, are you?

>>9240173
Text book does jack, so do my professors.

>>9240174
Let's be real, we're all turbo autists. I'm just a turbo autist whose in college

Anonymous

Anonymous Wed 18 Oct 2017 04:54:25 No.9240180 Report

Quoted By: >>9240183 >>9240184

>>9240174
We aren't doing your HW OP, it's not my fault you can't do basic simplification.

Anonymous

Anonymous Wed 18 Oct 2017 04:56:52 No.9240183 Report

Quoted By:

>>9240180
I'm not asking for you to solve it, I'm asking for help understanding it.

Anonymous

Anonymous Wed 18 Oct 2017 04:57:11 No.9240184 Report

Quoted By:

>>9240180
You know what they say about assuming, anon

Anonymous

Anonymous Wed 18 Oct 2017 05:16:00 No.9240212 Report

Quoted By: >>9240217

HS fag from third world nation here.
All these questions (except that cos(20+x), if you have to only use trigonometric identities) are easy.
61 is a rephrasal of sin^2x + cos^2x =1
You need to know that cscx = 1/sinx and secx=1/cosx for 67.

Anonymous

Anonymous Wed 18 Oct 2017 05:20:23 No.9240217 Report

Quoted By:

>>9240212

Thanks for actually trying to answer the question.
Can I eliminate both Cox^2x because they're above each other in the fraction or can I not because they have addition tagged to them?

Anonymous

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Anonymous Wed 18 Oct 2017 05:24:21 No.9240220 Report

Quoted By: >>9240235 >>9240240 >>9240248

What do after last step?

Anonymous

Anonymous Wed 18 Oct 2017 05:33:48 No.9240235 Report

Quoted By: >>9240254

>>9240220
Why have you not cross multiplied?
Just cross multiply and expand.

Anonymous

Anonymous Wed 18 Oct 2017 05:37:10 No.9240240 Report

Quoted By: >>9240254

>>9240220
Convert all cos to sin

Anonymous

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Anonymous Wed 18 Oct 2017 05:41:32 No.9240248 Report

Quoted By: >>9240254

>>9240220
Check pic related

Anonymous

Anonymous Wed 18 Oct 2017 05:44:28 No.9240253 Report

Quoted By: >>9240255 >>9240262

Guys, I'm working through 67 and I simplified it down to cot x = cot^3 x

The text book says that the solution is an identity, or that they're equal to each other. Did I do something wrong or does cot^3 x simply to just cot x?

Anonymous

Anonymous Wed 18 Oct 2017 05:45:18 No.9240254 Report

Quoted By:

>>9240235
>>9240248
>>9240240
got it. Thanks

Anonymous

Anonymous Wed 18 Oct 2017 05:45:27 No.9240255 Report

Quoted By: >>9240265

>>9240253
Nope, you did it wrong. I guess you cancelled stuff where you aren't supposed to. Look at it carefully.

Anonymous

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Anonymous Wed 18 Oct 2017 05:47:14 No.9240258 Report

Quoted By:

Holy shit you guys this is simple as fuck
Factor out the numerator

Anonymous

Anonymous Wed 18 Oct 2017 05:48:15 No.9240262 Report

Quoted By: >>9240264

>>9240253
OP just sub. cosec with 1/sin and sec with 1/cos, same for tan and cos.

You will get answer literally in 2 lines

Anonymous

Anonymous Wed 18 Oct 2017 05:48:58 No.9240264 Report

Quoted By:

>>9240262
Exactly.

Anonymous

Anonymous Wed 18 Oct 2017 05:51:41 No.9240265 Report

Quoted By: >>9240269 >>9240271

>>9240255

So I converted (csc x)(cot x)/(sec x)(tanx) into their inverse (leaving the top cot as it is) and got

(1/sin x)(cot x) / (1/cos x) (1/cot x)
I eliminated the cot till I was left with (1/sin x)/(1/cos x)
then that equals cot x. I'm where did I go wrong?

Anonymous

Anonymous Wed 18 Oct 2017 05:55:28 No.9240269 Report

Quoted By: >>9240274

>>9240265
(cotx)/(1/cotx) is the same as cotx * cotx/1, which is the same as cot^2x.
The rest becomes another cotx

WEW LAD

WEW LAD Wed 18 Oct 2017 05:56:51 No.9240271 Report

Quoted By:

>>9240265
(1/sinx)(cotx)/(1/cosx)(1/cotx) = (cosx/sinx).(cotx)^2 = cotx.(cotx)^2= RHS

Anonymous

Anonymous Wed 18 Oct 2017 05:57:50 No.9240274 Report

Quoted By: >>9240278

>>9240269
Yeah, I figured that out right before you posted.
Dividing fractions always confuses me for some reason.

Anonymous

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Anonymous Wed 18 Oct 2017 05:58:03 No.9240275 Report

Quoted By: >>9240280 >>9240298

Hijacking thread because OP probably got the answer. How do you do pic related?

Anonymous

Anonymous Wed 18 Oct 2017 05:59:24 No.9240278 Report

Quoted By:

>>9240274
You'll get it right with practice

Anonymous

Anonymous Wed 18 Oct 2017 06:00:27 No.9240280 Report

Quoted By:

>>9240275
Nvm this shit is easy

Anonymous

Anonymous Wed 18 Oct 2017 06:01:17 No.9240281 Report

Quoted By: >>9240534

>>9240157
(sin(x) + cos(x))^2 + (sin(x) - cos(x))^2 = 2
Result: True
Solution: x = ? + 2 n ?

Go to wolframalpha and put in the equations.

Anonymous

Anonymous Wed 18 Oct 2017 06:14:23 No.9240293 Report

Quoted By: >>9240296

That good feel when I couldn't do this in high school, but now I can do them all in my head

Anonymous

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Anonymous Wed 18 Oct 2017 06:15:14 No.9240294 Report

Quoted By: >>9240298 >>9240422

Somebody plox help

Anonymous

Anonymous Wed 18 Oct 2017 06:16:24 No.9240296 Report

Quoted By:

>>9240293
lol
I'm in high school and this is shit tier
Somebody pls help me solve my stupid problem

Anonymous

Anonymous Wed 18 Oct 2017 06:20:52 No.9240298 Report

Quoted By: >>9240300 >>9240307

>>9240275

>>9240294
JEE ?

Anonymous

Anonymous Wed 18 Oct 2017 06:22:49 No.9240300 Report

Quoted By:

>>9240298
Yes.

Anonymous

Anonymous Wed 18 Oct 2017 06:32:53 No.9240307 Report

Quoted By: >>9240312

>>9240298
Will someone help me solve the problem?

Anonymous

Anonymous Wed 18 Oct 2017 06:37:52 No.9240312 Report

Quoted By: >>9240317

>>9240307
Do you by chance have an equation sheet that came with your HW?

Anonymous

Anonymous Wed 18 Oct 2017 06:42:42 No.9240317 Report

Quoted By:

>>9240312
>equation sheet
It's DC Pandey. Answers are at the back. I just don't want to check it out. I want /sci/'s answers, could give me some insight.

Anonymous

Anonymous Wed 18 Oct 2017 08:25:05 No.9240395 Report

Quoted By:

>>9240173
>Textbook
>One short paragraph explanation
>Two examples that are nothing like the practice questions
Textbooks are fucking trash they always have been

Anonymous

Anonymous Wed 18 Oct 2017 08:57:16 No.9240422 Report

Quoted By: >>9240467

>>9240294
Solve it for n = 2, that's sufficient to eliminate the wrong answers.

Anonymous

Anonymous Wed 18 Oct 2017 10:00:06 No.9240467 Report

Quoted By:

>>9240422
Thanks.

Anonymous

Anonymous Wed 18 Oct 2017 11:03:41 No.9240534 Report

Quoted By:

>>9240281
Are you retarded?

Anonymous

Anonymous Wed 18 Oct 2017 12:05:19 No.9240601 Report

Quoted By:

Have of you guys are fucking tsunfags
>bitch but still help

Anonymous

Anonymous Wed 18 Oct 2017 14:49:41 No.9240774 Report

Quoted By:

largely a waste of time, in quantum mechanics and physics etc. youj are never going to use trig identities but eulers equation instead

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