Oblicz sin alpha, tg alpha, ctg alpha, wiedząc że cos alpha = frac{2}{7}.  

cosα = 2/7,  α ∈ (I lub IV ćwiartki) sinα, tgα, ctgα = ?   cosα = 2/7         sin²α + cos²α = 1         sin²α = 1-cos²α = 1-(2/7)² = 49/49 - 4/49 = 45/49 sinα = √(45/49) =  3√5/7   v   sinα = -3√5/7 tgα = sinα/cosα = 3√5/7 : 2/7 = 3√5/2   v tgα = -3√5/2 ctgα = 1/tgα = (2/7)* 7/3√5 * √5/√5 = 2√5/15    v  ctgα = -2√5/15    

[latex]\cosalpha=frac27, alpha in I lub IV cw. \sin^2alpha+cos^2alpha=1 \sin^alpha+(frac27)^2=1 \sin^2alpha=1-frac{4}{49} \sin^2alpha=frac{45}{49} \sinalpha=frac{sqrt45}{7}=frac{3sqrt5}{7} vee sinalpha=-frac{3sqrt5}{7} \tgalpha=frac{sinalpha}{cosalpha}, ctgalpha=frac{1}{tgalpha} \tgalpha=frac{3sqrt5}{2} vee tgalpha=-frac{3sqrt5}{2} \ctgalpha=frac27*frac{7}{3sqrt5}=frac{2sqrt5}{15} vee ctgalpha=-frac{2sqrt5}{15} [/latex]

Wiedząc że sin [latex]alpha[/latex] = [latex]frac{2}{5}[/latex] oblicz cos [latex]alpha[/latex], tg [latex]alpha[/latex], ctg [latex]alpha[/latex].

Wiedząc że sin [latex]alpha[/latex] = [latex]frac{2}{5}[/latex] oblicz cos [latex]alpha[/latex], tg [latex]alpha[/latex], ctg [latex]alpha[/latex]....

Oblicz  cos[latex] alpha [/latex], tga [latex] alpha [/latex] i ctg[latex] alpha [/latex] wiedząc że sin[latex] alpha [/latex] wynosi [latex] frac{1}{7} [/latex]

Oblicz  cos[latex] alpha [/latex], tga [latex] alpha [/latex] i ctg[latex] alpha [/latex] wiedząc że sin[latex] alpha [/latex] wynosi [latex] frac{1}{7} [/latex]...