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kaylala
 2 years 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)
kaylala
 2 years 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
 2 years ago
Best ResponseYou've already chosen the best response.1I do not understand what comes after 4/5 and 3/5

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

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

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

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

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

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

Yttrium
 2 years 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
 2 years ago
Best ResponseYou've already chosen the best response.0@eliassaab here's the picture

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

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

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

Yttrium
 2 years 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
 2 years ago
Best ResponseYou've already chosen the best response.0oh okay i see now @Yttrium

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

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

Yttrium
 2 years 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
 2 years 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
 2 years ago
Best ResponseYou've already chosen the best response.0okay x=sqrt9 ??? @Yttrium

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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