A⃗=2î+3ĵ+6k̂ and B⃗=2î−6ĵ+2k̂. If A⃗×B⃗=7aî+4bĵ+6ck̂, find a+b+c.
Physics · Mixed Chapter
JEE Main Practice

Question

A⃗=2î+3ĵ+6k̂ and B⃗=2î−6ĵ+2k̂. If A⃗×B⃗=7aî+4bĵ+6ck̂, find a+b+c.

G1 Physics · Accepted Answer

Step 1: Calculate A⃗×B⃗ = [3×2−6(−6)]î + [6×2−2×2]ĵ + [2(−6)−3×2]k̂. Step 2: This is 42î+8ĵ−18k̂. Step 3: Therefore 7a=42⇒a=6; 4b=8⇒b=2; 6c=−18⇒c=−3. Step 4: Sum a+b+c=6+2−3=5.