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Math4Life
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Find the value of tan (ab) if cos a = 3/5 , sin = b 5/13, 0° < a < 90°, and 0° < b < 90°
 one year ago
 one year ago
Math4Life Group Title
Find the value of tan (ab) if cos a = 3/5 , sin = b 5/13, 0° < a < 90°, and 0° < b < 90°
 one year ago
 one year ago

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Math4Life Group TitleBest ResponseYou've already chosen the best response.0
@hartnn think you could help me on this one? :)
 one year ago

hartnn Group TitleBest ResponseYou've already chosen the best response.0
know the formula for tan(ab) ??
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
kind of, i'm doing an alternative thing for my teacher where we try to work ahead on stuff we haven't learned yet so I don't really understand the concept, I want the answer because it gives me extra credit, but I want to understand and for you to explain it to me so I know how to do it for the future :)
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
@Callisto @campbell_st @completeidiot
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
you need to find the missing sides in 2 triangles dw:1357801664006:dw find x and y using pythagoras' theorem... this should be easy. then find for angle a.... the ratio for tan(a) and for angle b.... the ratio for tan(b) then substitute the ratios into the expansion of tan(a  b) hope this makes sense
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
It kind of makes sense, do you think you could work through the problem with me?
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
ok... what are the lengths of x and y...?
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
well we haven't figured them out yet
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
can you calculate them using pythagoras' theorem \[5^2 = 3^2 + x^2\] and \[13^2 = 5^2 + y^2\]
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
x = 4, 4 y = 12, 12
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
well with mesurements... you can only use the positives... you can show me 3 metres... but you can show me 3 metres ok... next step what is tan(a) = and tan(b) = both answers will be fractions...
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
1.1578 or 1.1578 0.2126 or 0.2126 right?
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
nope not as decimals as fractions... just like in the question cos(a) = 3/5 you need to write them like that
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
and only use positive values...
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
Ok well let me convert them to fractions
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
remember tan = opp/adjdw:1357802645909:dw
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
22/19 and 7/33
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
not even close... you said x = 4 and y = 12 so what would tan(a) = and tan (b) =
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
dw:1357802809114:dw
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
a as in x and b as in y, correct?
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
use the measurements in the drawing above to write fractions for tan(a) = and tan (b) =
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
I am so confused right now, how do i solve for a and b?
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
ok... do you understand that tan = opposite/adjacent... ?
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
ok... from the diagram below dw:1357803166503:dw what is tan(a) = just write a fraction using the side measurements given
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
great tan(a) = 4/3 now for angle b dw:1357803706601:dw what is tan(b) = as a fraction
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
not quite tan = opposite/adjacent so tan(b) = 5/12 ok... do you know the expansion of tan(a  b)....?
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
So tan(4/3  5/12) which is 30/23
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
nope start with the expansion \[\tan(a  b) = \frac{\tan(a)  \tan(b)}{1 + \tan(a)\tan(b)}\] so substitute tan(a) = 4/3 and tan(b) = 5/12 then just calculate it out...
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
oops it should read \[\tan(a  b) =\frac{ \tan(a)  \tan(b)}{1 + \tan(a)\times \tan(b)}\]
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
tan(4/3  5/12) = tan(4/3)  tan(5/12)/1 + tan(4/3) tan(5/12)
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
nope... just put the fractions in (4/3  5/12)/(1 + 4/3 x 5/12)
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
which is 33/35
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
is 33/35 my final answer?
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
Ok i'm not trying to seem pushy but can we hurry it up here? It's 3am here and I have to get up at 5:30am and this is my last problem on my practice test
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
I appreciate all your help and time thank you :)
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
good luck... you really need to know trig basics to be able to do this problem.
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
If I keep working on this with you how long will it take? because I'm extremely tired
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
well your answer is close it should be 33/56
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
Thank you for everything tonight
 one year ago

campbell_st Group TitleBest ResponseYou've already chosen the best response.2
good luck
 one year ago

Math4Life Group TitleBest ResponseYou've already chosen the best response.0
Thank you I appreciate it
 one year ago
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