SOLUTION: 1)If sinA=sinB and cosA=cosB then A=______. 2)If (1+tan x)(1+tan y)=2 then x+y=_____. 3)If tanx+tan(60°+x)+tan(120°+x)=3 then x=______. 4)1+ sinx +sin^2x..........=4

1)If sinA=sinB and cosA=cosB then A=B or else they differ by  or 
 

Since the period of sine and cosine is  or 360°, the general solution is 
 or A = B + 360°n, where n is any integer   

2)If 
 then _____.

FOIL out the left side:

If we remember our identities and also notice that we are 
asked to find x+y, and notice that there are tangents in
the problem and then we we think of the identity we 
have memorized for tan(x+y)

We recognize some of the terms in our equation are like some
of the terms in that identity so let's get tan(x)+tan(y) alone
on the left side since that's the numerator of the right side
of that identity:




Well what do you know! the right side is just the denominator 
of the right side of that identity: 
So we divide both sides by the right side:    
 
  
The left side is the left side of that identity and the right side is 1. 
So we have


Since the period of the tangent is  or 180°
x+y =  or 45°+180°n, where n is any integer, positive,
negative, or zero. 

Limit: 2 problems

Edwin