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tan help needed

theta is an acute angle and sin theta =1/4 find the exact value of tan

isnt tan=costheta/sintheta?

how do i answer this

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Reply 1
If sin = 1/4

then opp=1 and hyp=4

what is adj

hence what is tan
Reply 2
--- mistake
Reply 3
Original post by TenOfThem
If sin = 1/4

then opp=1 and hyp=4

what is adj

hence what is tan


tan is o/a

so i know what opposite is as its 1

but i dont have the adjacent
Reply 4
Original post by TenOfThem
If sin = 1/4

then opp=1 and hyp=4

what is adj

hence what is tan


is the h square root of 5
Reply 5
Original post by dongonaeatu
tan is o/a

so i know what opposite is as its 1

but i dont have the adjacent


but you do have 2 sides so surely you know how to find adj
Reply 6
Original post by dongonaeatu
is the h square root of 5


no, h = 4
Reply 7
Original post by TenOfThem
but you do have 2 sides so surely you know how to find adj


is it square root of 5
Reply 8
Original post by TenOfThem
no, h = 4


sorry, is adjacent square root of 5
Reply 9
Original post by dongonaeatu
is it square root of 5


no

how do you get that
Original post by dongonaeatu
theta is an acute angle and sin theta =1/4 find the exact value of tan

isnt tan=costheta/sintheta?

how do i answer this


sin(T) = opp/hyp

So draw out the triangle. Use Pythagoras (hyp^2 = adj^2 x opp^2) to calculate adj

tan(T) = opp/adj
Reply 11
Original post by TenOfThem
no

how do you get that


is it 5^2
Original post by dongonaeatu
is it 5^2


What are you doing to get these numbers

You have a right angled triangle

The Hyp = 4

The Opp = 1

You are looking for the third side


Remind me what exam level you are studying for
Reply 13
Original post by lukas1051
sin(T) = opp/hyp

So draw out the triangle. Use Pythagoras (hyp^2 = adj^2 x opp^2) to calculate adj

tan(T) = opp/adj


doesnt it equal 5 then?
Reply 14
Original post by TenOfThem
What are you doing to get these numbers

You have a right angled triangle

The Hyp = 4

The Opp = 1

You are looking for the third side


Remind me what exam level you are studying for


okay so pythagorus therom a^2+b^2=c^2
4^2+1^2=c^2
16+1=c^2
c= square root of 17
so the a = square root of 17?
AS level c2
I don't know how much trigonometry you know, but I'll try and be as simple as possible. sin is opposite over hypotenuse, tangent is opposite over adjacent. Since sinx=1/4, we assume the opposite is 1 and the hypotenuse is 4. Pythagoras' theorem tells us that the adjacent length is sqrt(15). Hence, tanx=1/sqrt(15).
Reply 16
so from sin(x) = 1/4 we know that:

opp= 1 hyp= 4

so by Pythagoras' Theorem: opp^2 + adj^2= hyp^2

rearranging to get adj = sqrt(hyp^2-opp^2)

so adj = sqrt(4^2 - 1^2) = sqrt(16 - 1) = sqrt(15)

And as tan(x) = opp/adj

so tan(x) = 1/sqrt(15)
(edited 11 years ago)
Original post by dongonaeatu
okay so pythagorus therom a^2+b^2=c^2
4^2+1^2=c^2
16+1=c^2
c= square root of 17
so the a = square root of 17?
AS level c2

Remember c is the longest side! So you have 1+b^2=16.
b=sqrt(15)
Original post by dongonaeatu
okay so pythagorus therom a^2+b^2=c^2
4^2+1^2=c^2
16+1=c^2
c= square root of 17
so the a = square root of 17?
AS level c2


c = hypotenuse..

so a^2 + b^2 = c^2

a^2 + 1^2 = 4^2
Original post by dongonaeatu
okay so pythagorus therom a^2+b^2=c^2
4^2+1^2=c^2
16+1=c^2
c= square root of 17
so the a = square root of 17?
AS level c2


No. The hypotenuse, c = 4. You are looking for the adjacent side (a or b)

4^2 = 1^2 + b^2

4^2 - 1^2 = b^2

16 - 1 = b^2

15 = b^2

b = adj = sqrt(15)

You now how the opposite and adjacent sides. What does tan(T) now equal?

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