נתון:
צ"ל:
הוכחה:
∠ β = 90 ∘ ∠ α = 60 ∘ ↓ ∠ A = 90 ∘ − 60 ∘ = 30 ∘ ↓ O B = 1 2 O A ( △ ) A O = 1 c m = r ( U n i t c i r c l e s ) ↓ cos ( α ∘ ) = O B = 1 2 ↓ ( 1 2 ) 2 + A B 2 = 1 A B 2 = 1 − 1 4 = 3 4 A B = 3 4 = 3 2 {\displaystyle {\begin{aligned}&\angle \beta =90^{\circ }\\&\angle \alpha =60^{\circ }\\&\downarrow \\&\angle A=90^{\circ }-60^{\circ }=30^{\circ }\\&\downarrow \\&OB={\frac {1}{2}}OA({\color {Gray}\triangle })\\&AO=1_{cm}=r(Unitcircles)\\&\downarrow \\&{\color {blue}\cos(\alpha ^{\circ })=OB={\frac {1}{2}}}\\&\downarrow \\&({\frac {1}{2}})^{2}+AB^{2}=1\\&AB^{2}=1-{\frac {1}{4}}={\frac {3}{4}}\\&{\color {blue}AB={\sqrt {\frac {3}{4}}}={\frac {\sqrt {3}}{2}}}\\\end{aligned}}}
ע"פ הנחה זו נוכל למצוא את tan ( 60 ∘ ) {\displaystyle \tan(60^{\circ })} :
tan ( 60 ∘ ) = sin ( 60 ∘ ) cos ( 60 ∘ ) 3 2 1 2 = 3 1 = 3 {\displaystyle \tan(60^{\circ })={\frac {\sin(60^{\circ })}{\cos(60^{\circ })}}{\frac {\frac {\sqrt {3}}{2}}{\frac {1}{2}}}={\frac {\sqrt {3}}{1}}={\sqrt {3}}}