General solution of the equation : `sinx + cos x= min_(aepsilonR) {1,a^2-4a+6}` is :

Explanation

`min(1,a^2-4a+6)`

`f(a)=a^2-4a+6`

`f'(a)=2a-4`

`f'(a)=0`

`f'(a)=2>0`

`f(2)=4-8+6=2`

`min(1,a^2-4a,6)=>1`

`1/sqrt2(sinx+cosx)=1*1/sqrt2`

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