Answer: 2sin^2x+sin2x+cos2x=0 ..... (1).
By using the trigonometric identities below : 
sin2x=2sinxcosx 
cos2x=cos^2x-sin^2x 
We substitute the trigonometric identities into (1).
2sin^2x+2sinxcosx+cos^2x-sin^2x=0
By combining like terms . 
sin^2x+2sinxcosx+cos^2x=0.....(2)
The equation (2) is equivalent to the following expression (3).
(sinx+cosx)(sinx+cosx)=0 .....(3).
sinx+cosx=0
cosx=-sinx
divide both sides by cosx
1=-sinx/cosx
-1=sinx/cosx
sinx/cosx=tanx
substitute
-1=tanx
tanx=-1
tangent is negative in 2nd and 4th quadrants
tan135º=-1 (one answer)
tan315º=-1 (second answer)
Step-by-step explanation:
Please refer to the trigonometric identities used and explained above .
 
        
             
        
        
        
Answer:
The twentieth term is 50.
Step-by-step explanation:
The equation that describes the arithmetic sequence describes it's "general term", which means that all the numbers in that sequence must follow that equation. For instance, if we want to find the first term of the sequence we must make a = 1 and we have:
a1 = 3*1 - 10 
a1 = -7
Therefore to find the twentieth term we need to make n equal to 20. This is done below:
a20 = 3*20 - 10
a20 = 60 - 10
a20 = 50
The twentieth term is 50.
 
        
             
        
        
        
I’m sorry i don’t speak Spanish!
        
             
        
        
        
Answer:
13. 0.145, 0.18, 0.206, 0.315
14. 1.75 times
<u><em>WARNING</em></u>
<em>im not completely sure sooo, Im really really sorry if you get it wrong</em>