Question

(d) cos80 + sin80 = 1 - sin²20 + = sin420.​

Answer 1

Answer:

Step-by-step explanation:

Multiplying and dividing by  

2

​

 

=  

2

​

(  

2

​

 

sin80  

0

 

​

−  

2

​

 

cos80  

0

 

​

)

=  

2

​

[sin(80  

0

−45  

0

)]

=  

2

​

sin35  

0

 

Hence False.

Alternatively,

sinθ increases as θ increases.

While cosθ decreases as θ increases. for 0≤θ≤90  

0

 

Hence the answer will be false.