найти значение [sin(a) + cos(a)]/[sin(a) - cos(a)]^-1, если sin(2a)=-0,6 ; 90`<a<135`
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найти значение [sin(a) + cos(a)]/[sin(a) - cos(a)]^-1, если sin(2a)=-0,6 ; 90`<a<135`
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(sin a+cos a)/(sin a-cos a)^-1
(sin a+cos a)*(sin a-cos a)=sin^2 a-cos^2 a=-(cos^2 a-sin^2 a)=-cos 2a
sin 2a=-0.6
cos 2a=-(sqrt(1-sin^2 2a))=-(sqrt(1-0.36))=-(sqrt 0.64)=-0.8
-(-0.8)=0.8
Ответ: 0.8