Task/26548397
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1.tgα =sinα / cosα = -√(1 -cos²α) / cosα = -√(1 -1/10) / 1/√10 = - 3.
* * * α∈(3π/2 ;2π) , sinα < 0 * * *
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2. tgα =sinα / cosα = sinα /( - √(1 -sin²α) ) =( -5/√26 ) / ( -√( 1 -( -5/√26 )²) = 5.
* * * α∈(π; 3π/2 ) , cosα < 0 * * *
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3. 3cosα = 3√(1 -sin²α) ) =3√( 1 -( -2√2 /3 )² ) = 3√(1 -8/9) =3√(1/9) =3*1/3 =1.
* * * α∈(3π/2 ; 2π ) , cosα > 0 * * *