Question

if (sinx+2 cosx)(cosx+2 sinx)=9/2 then x is

Answer 1

Answer:

Correct option is

B

2nπ+  

4

3π

​

 

Given that, sinx−cosx=  

2

​

 

⇒  

2

​

 

1

​

sinx−  

2

​

 

1

​

cosx=1

sin45  

∘

sinx−cos45  

∘

cosx=1

⇒cos(x+  

4

π

​

)=−1

⇒cos(x+  

4

π

​

)=cos(π)

⇒x+  

4

π

​

=2nπ+π

⇒x=2nπ+  

4

3π

​

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Step-by-step explanation: