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Confusionist
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Can someone help me solve this?
cos(x^2+45)+tan(4x+90) = sin(3x+120)
A step by step would be great.
 9 months ago
 9 months ago
Confusionist Group Title
Can someone help me solve this? cos(x^2+45)+tan(4x+90) = sin(3x+120) A step by step would be great.
 9 months ago
 9 months ago

This Question is Closed

xlegendx Group TitleBest ResponseYou've already chosen the best response.0
by solving do you mean proving?
 9 months ago

Confusionist Group TitleBest ResponseYou've already chosen the best response.1
Yes. :)
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
What methods have been discussed?
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
We are solving for x not proving this. This isn't an identity.
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
Or does it say to disprove or prove?
 9 months ago

Confusionist Group TitleBest ResponseYou've already chosen the best response.1
Ah yes, my bad. It says solve.
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
Can you tell me what methods in class have been discussed?
 9 months ago

Confusionist Group TitleBest ResponseYou've already chosen the best response.1
None, this is from a book with only problems I picked up at barnes and noble. We haven't done this and wont do it for another year or two. I've had no problems with the book up to this point.
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
can you tell me what methods the book has discussed?
 9 months ago

Confusionist Group TitleBest ResponseYou've already chosen the best response.1
None. It's a book of only problems. It starts from Geometry and works it's way up in problems.
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
Name of book please
 9 months ago

Confusionist Group TitleBest ResponseYou've already chosen the best response.1
Math Review for the High School Classroom
 9 months ago

Confusionist Group TitleBest ResponseYou've already chosen the best response.1
I looked for it online and can't find it.
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
I didn't see the book. :( So there are no examples?
 9 months ago

Confusionist Group TitleBest ResponseYou've already chosen the best response.1
No examples, just questions. :c How did you learn it?
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
Honestly, I don't know without seeing some example or them mentioning some method they want to use.
 9 months ago

Confusionist Group TitleBest ResponseYou've already chosen the best response.1
Ah, okay. Thanks, anyway. :)
 9 months ago

shamil98 Group TitleBest ResponseYou've already chosen the best response.0
cos(x^2+45)+tan(4x+90) = sin(3x+120) cos(x^2+45)+sin/cos(4x+90) = sin(3x+120) dividing everything by sin. tan(x^2+45) + sec(4x+90) = 3x + 120 i don't remember trig that well, but you can convert it to this i think.
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
You can't do that... Like you can't divide by the trig part The trig part is a function not a number or variable on its own
 9 months ago

primeralph Group TitleBest ResponseYou've already chosen the best response.1
Are the angles in radians or degrees?
 9 months ago

primeralph Group TitleBest ResponseYou've already chosen the best response.1
I'll assume degrees for now.
 9 months ago

Confusionist Group TitleBest ResponseYou've already chosen the best response.1
Degrees, yeah. ^^
 9 months ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
45,90,120 suggest they are in degrees... we can convert sin and cos in tan, like cos A = tan (sqrt (1A^2)/A) something like this and then use tan A+tan B formula...... but if thats possible, the algebra is going to be very ugly....
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
but @hartnn tan(90) does not exist you were talking about the sum identity for tan right?
 9 months ago

primeralph Group TitleBest ResponseYou've already chosen the best response.1
@myininaya tan(a+90) = 1/tan(a), since they're perpendicular.
 9 months ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
not tan(A+B) tan A +tan B , where B = 4x+90 and yeah, tan (A+90) =  cot 90 so maybe convert cos into cot and use cotAcotB formula... i don't think that will be of any use though....
 9 months ago

primeralph Group TitleBest ResponseYou've already chosen the best response.1
dw:1388481204906:dw
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
I don't like the x squared part much.
 9 months ago

primeralph Group TitleBest ResponseYou've already chosen the best response.1
Series solution is what I'd prefer to us,e but not without an attempt with standard algera.
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
or maybe the whole problem i don't see how to do it with algebra/trig He said it was for high school though
 9 months ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
even wolf doesn't give integral or rational solutions...
 9 months ago

Confusionist Group TitleBest ResponseYou've already chosen the best response.1
Yes, I'm a junior in high school, but the book said High School. It extends way past what I expect to learn in High School, though. I think they may have the age range a bit messed up.
 9 months ago

primeralph Group TitleBest ResponseYou've already chosen the best response.1
No simple way to solve at that level.
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
@primeralph if you want, can you show me your series thing you were talking about? You know if you want to.
 9 months ago

Confusionist Group TitleBest ResponseYou've already chosen the best response.1
I might just go and ask one of the professors at the college I intern at. Thanks for your help, guys. :)
 9 months ago

primeralph Group TitleBest ResponseYou've already chosen the best response.1
First I'd have to convert all to radians.
 9 months ago

primeralph Group TitleBest ResponseYou've already chosen the best response.1
Then find a way to represent the equation as a DE, or simply use the Taylor power series.
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
what is equivalent to a (1 radian) squared? That bugs me. The little square there.
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
What I'm saying is I'm not used to looking at angles being squared
 9 months ago

primeralph Group TitleBest ResponseYou've already chosen the best response.1
dw:1388481895287:dw
 9 months ago

primeralph Group TitleBest ResponseYou've already chosen the best response.1
@myininaya Yeah I understand, but you'd have to extend your thinking beyond expecting trig to only apply to angles.
 9 months ago

primeralph Group TitleBest ResponseYou've already chosen the best response.1
It will be extensive, but in the end, there might be real solutions.
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
x^2 and 45 will have different units
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
we have x^2=a^2 (degs)^2 and 45 is just in degs not degs^2
 9 months ago

primeralph Group TitleBest ResponseYou've already chosen the best response.1
The x^2 term will be set to have some correction factor. After taking a look at it, I think it's solvable algebraically. It's just long.
 9 months ago

primeralph Group TitleBest ResponseYou've already chosen the best response.1
And with a lot of restrictions to be imposed.
 9 months ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
those ugly solutions http://www.wolframalpha.com/input/?i=cos%28x%5E2%2B45%29%2Btan%284x%2B90%29+%3D+sin%283x%2B120%29&dataset=
 9 months ago

primeralph Group TitleBest ResponseYou've already chosen the best response.1
Don't think you used radians. Wolfram is radians by default.
 9 months ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
doesn't make much difference http://www.wolframalpha.com/input/?i=cos%28x%5E2%2Bpi%2F4%29%2Btan%284x%2Bpi%2F2%29+%3D+sin%283x%2B2pi%2F3%29
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
wolfram doesn't want to solve it this is the way input it cos((x deg)^2+45 deg)+tan(4x deg+90 deg)=sin(3x deg+120 deg) http://www.wolframalpha.com/input/?i=cos%28%28x+deg%29%5E2%2B45+deg%29%2Btan%284x+deg%2B90+deg%29%3Dsin%283x+deg%2B120+deg%29
 9 months ago

myininaya Group TitleBest ResponseYou've already chosen the best response.3
Maybe it doesn't like the unlike units being added either idk
 9 months ago
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