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 11 months ago
TOPIC: Trigonometry
GIVEN THE FOLLOWING CONDITIONS:
sin A = 4/5, A Σ I
sin B = 3/5, B Σ III
Find the value of:
I. sin (A + B)
II. cos (A + B)
III. tan (A + B)
 11 months ago
TOPIC: Trigonometry GIVEN THE FOLLOWING CONDITIONS: sin A = 4/5, A Σ I sin B = 3/5, B Σ III Find the value of: I. sin (A + B) II. cos (A + B) III. tan (A + B)

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eliassaab
 11 months ago
Best ResponseYou've already chosen the best response.1I do not understand what comes after 4/5 and 3/5

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0let me fix the question

eliassaab
 11 months ago
Best ResponseYou've already chosen the best response.1Also look at this summary of trig formulas, your problem follows easily http://www.math.missouri.edu/escgi/mucgibin/trigidentities.cgi

eliassaab
 11 months ago
Best ResponseYou've already chosen the best response.1It is still not fixed

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0it is. see this pic that i will post. it's where i got the question. wait

eliassaab
 11 months ago
Best ResponseYou've already chosen the best response.1You need these formulae sin(a + b ) = sin(a) cos(b) + sin(b) cos(a) sin(a  b ) = sin(a) cos(b)  sin(b) cos(a) cos(a + b ) = cos(a) cos(b)  sin(a) sin(b) cos(a  b ) = cos(a) cos(b) + sin(a) sin(b)

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0oh it's (+_) the plus on top of the minus for I  III

eliassaab
 11 months ago
Best ResponseYou've already chosen the best response.1You do first + than 

eliassaab
 11 months ago
Best ResponseYou've already chosen the best response.1You need six answers

eliassaab
 11 months ago
Best ResponseYou've already chosen the best response.1Where is the picture?

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0wait. i just took a picture of it

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2@eliassaab , I think the information beside 4/5 and 3/5 are the position of angle in the cartesian plane. (specifically Quadrant I for <A and Quadrant III for <B

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0@eliassaab here's the picture

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0and yes those are values for the carthesian plane @Yttrium

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0i dont think i have to find 6 answers @eliassaab

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0somebody. anyone. please help

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2You really have to find 6 ansers @kaylala. Let me tell you this: \[\sin (A \pm B)\] is the notation for\[\sin (A+B)\] and \[\sin(AB)\] I hope you understand now.

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0oh okay i see now @Yttrium

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0i just dont know how to start this

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2let's start with angle A

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2the condition says sinA = 4/5, where it is in quadrant 1. we know that sinx = opp/hyp Hence, the figure much look like this. dw:1391508636187:dw

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2dw:1391508787128:dw let's say that adjacent side of A is x. Can you solve x now?

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0okay x=sqrt9 ??? @Yttrium

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2isn't is sqrt(+9)? which is 3?

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2Yea it is. And, with that you can now actually solve for cosA, tanA.

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0i really dont know how to do this please guide me @Yttrium

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2cosA = adj/hyp tanA = opp/adj did you forget that?

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2You got this. I think it is better if you write sinA, cosA, and tanA in a piece of paper. They are really important later. Next thing we are going to do is to solve for cosB and tanB

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0yeah. just wrote it down already how do i solve for that?

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2you sure? isn't it 4? take note it is in the quadrant III.

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0okay so the quadrant determines the sign? right?

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2Yeah. for (x,y) quadrant I (+,+) II (,+) III (,) IV (+,) Now. Find cosB and tanB. Be careful with the signs.

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2Solve for cosB and tanB

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2the graph will be like this dw:1391510194742:dw

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2x then is 4 solve again for cosB and tanB

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0i see now but the answer for cos b and tan B still remains?

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0so are those the answers already?

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2ooops tanB = 3/4 = 3/4

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2Now is the time to evaluate them. I. sin (A + B) = sinAcosB + cosAsinB II. cos (A + B) = cosAcos + sinAsinB

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2III. \[\tan(A \pm B) = \frac{ tanA \pm tanB }{ 1\mp tanAtanB }\]

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0how's that? do i just substitute what i got? to the given formulas?

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2Yeah. All the operation found upside are the only operations used when applying upside identities. Look at this. \[\tan(A +B) = \frac{ tanA + tanB }{ 1  tanAtanB }\]

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0so sin(a+b) = 1 sin(ab) = 7/25 ??? @Yttrium

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0cos (a+b)=0 cos (ab)=24/25 did i get it correctly @Yttrium ?

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2i'll just check the sin function, you take care of the others :D sin(a+b) = 1

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0tan (A+B)= undefined??? is it? please check this @Yttrium

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2what is tanA and tanbB?

Yttrium
 11 months ago
Best ResponseYou've already chosen the best response.2Yeah. That's undefined. And that is normal. :))

kaylala
 11 months ago
Best ResponseYou've already chosen the best response.0i see. okay thanks again :)
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