Question

Calculatia expresia 2-3sin patrat x , daca se stie ca cosx= -0,3

Answer 1

Stim ca sin patrat de x + cos patrat de x=1=> sin patart de x=1-cos patrat de x
=>sin patrat de x= 1-(-0.3)la patrat=1+0.09
Inlocuim in expresie 2-3(1+0.09)=2-3-0.27=-1-0.27=-1.27

Answer 2

   
[tex]\texttt{Folosim formula: } \\ sin^2x + cos^2 x = 1 ~~~~\Longrightarrow~~~~ sin^2 x = 1 - cos^2 x \\ \\ 2-3sin^2x = \\ = 2-3(1 - cos^2 x )= \\ =2-3+3cos^2x = \\ =-1+3cos^2x = \\ = -1+3\cdot (-0,3)^2= \\ = -1+3 \cdot (0,09)= -1 + 0,27 = \boxed{ -0,73 } [/tex]