If two vectors and are perpendicular to each other. Then, the value of will be:

Question

If two vectors  and  are perpendicular to each other. Then, the value of  will be:

Canvas Classes · Accepted Answer

🧠 Perpendicular Vectors: Dot Product = 0

Read the question slowly. The single keyword is "perpendicular". Two vectors are perpendicular if and only if their dot product is zero. That's the entire framework — compute , set it to zero, solve for .

The first move is always: write the dot product with the unknown left as a variable, set equal to zero, then solve the resulting equation (here, a quadratic in ).

🗺️ Working It Out

.

Set equal to zero:

.

So  — option (b).

⚡ The Smart Move

For

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