# trigonometry: (A2) Compound angles question

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#1
Hi,

Could someone help me out with what this questions asking me exactly?

Thanks 0
1 month ago
#2
(Original post by dxnixl)
Hi,

Could someone help me out with what this questions asking me exactly?

Thanks It is asking you to find the value of such that 0
#3
oH! thankyou so i’m assuming x and are two different variables?

sorry if i’m a bit slow we just went over this today ergh
0
1 month ago
#4
(Original post by dxnixl)
oH! thankyou so i’m assuming x and are two different variables?

sorry if i’m a bit slow we just went over this today ergh
x is the variable.

Alpha is a constant value.
0
#5
(Original post by RDKGames)
x is the variable.

Alpha is a constant value.
so is the answer 45 because x and alpha must be the same so that alphas eliminated on the RHS?

or am i just lost :’)
0
1 month ago
#6
(Original post by dxnixl)
so is the answer 45 because x and alpha must be the same so that alphas eliminated on the RHS?

or am i just lost :’)
If "x and alpha must be the same", then surely x = alpha? I don't think that's what you actually meant to say...
0
1 month ago
#7
(Original post by dxnixl)
Hi,

Could someone help me out with what this questions asking me exactly?

Thanks Starting with: tan(x + a) = (tan a + tan x) / (1 - tan a tan x)
Notice that if tan a = 1, then the expression becomes identical to what is in the question: (1 + tan x) / (1 - tan x)
So let a = arctan(1) = pi/4 to get tan(x + pi/4).

Edit: or tan(x + 45) if working in degrees instead of radians.

Hope this helps Last edited by Nick_2440; 1 month ago
0
#8
(Original post by Nick_2440)
Starting with: tan(x + a) = (tan a + tan x) / (1 - tan a tan x)
Notice that if tan a = 1, then the expression becomes identical to what is in the question: (1 + tan x) / (1 - tan x)
So let a = arctan(1) = pi/4 to get tan(x + pi/4).

Hope this helps OH RIGHT yeah i got it now ergh thanks 🤦*♂️
because tan(alpha) has to equal 1 to get the 1 in the numerator and so alpha can only be 45 degrees
thanks 0
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