- #1
SeReNiTy
- 170
- 0
Hi, i was required to show that
-1 < [tex] \frac{a.b}{\|{a}\|\|{b}\|}} [/tex] > -1
I did this by using the cosine rule which is [tex] c^2 = a^2 + b^2 - 2a.b\cos{\vartheta} [/tex]
How ever our teacher did it by a scharts proof which i don't quite understand, , Now my question is why can't i prove it using the cosine rule and could somebody explain the schwartz proof a bit better?
-1 < [tex] \frac{a.b}{\|{a}\|\|{b}\|}} [/tex] > -1
I did this by using the cosine rule which is [tex] c^2 = a^2 + b^2 - 2a.b\cos{\vartheta} [/tex]
How ever our teacher did it by a scharts proof which i don't quite understand, , Now my question is why can't i prove it using the cosine rule and could somebody explain the schwartz proof a bit better?