Question

$|\overset{\rightarrow}{a}=5|, |\overset{\rightarrow}{b}|=6, \overset{\rightarrow}{a}.\overset{\rightarrow}{b}=-25$ ആയാൽ $|\overset{\rightarrow}{a} \times \overset{\rightarrow}{b}|=$

• A. 25
• B. 6√11
• C. 11√5
• D. 5√11

Answer 1

Answer:

D. 5√11

$|\overset{\rightarrow}{a} \times \overset{\rightarrow}{b}|^2 + |\overset{\rightarrow}{a} . \overset{\rightarrow}{b}|^2= |\overset{\rightarrow}{a} |^2| \overset{\rightarrow}{b}|^2$

$|\overset{\rightarrow}{a} \times \overset{\rightarrow}{b}|^2+(-25)^2=5^2 \times 6^2$

$|\overset{\rightarrow}{a} \times \overset{\rightarrow}{b}|^2=25(36-25)$

=25 x 11

=$|\overset{\rightarrow}{a} \times \overset{\rightarrow}{b}|=5\sqrt{11}$