Topic Details (Notes format)

How to Calculate Dot Product and Angle Between Two Vectors

Subject: Mathematics

Book: Maths Mastery

The dot product u20d7A · u20d7B=|A||B|cos(θ)=a₁b₁+a₂b₂ (in 2D). If u20d7A · u20d7B>0, the angle is acute; <0, obtuse; =0, vectors are perpendicular. For instance, with u20d7A=[3,4] and u20d7B=[4,3], u20d7A · u20d7B=3×4+4×3=24, magnitudes |A|=5,|B|=5, so cos(θ)=24/25→θ=cos⁻¹(24/25)=16.26°. This measure underlies geometry (orthogonal checks), physics (work= u20d7F · u20d7d), and advanced math transformations. Dot product mastery fosters deeper vector analysis crucial in multi-dimensional calculus or engineering design tasks.

Practice Questions

If a:b = 3:4 and b:c = 5:6, what is a:c?

View Question

If sin(A) = 1/2 and A is acute, what is the value of A?

View Question

What is the remainder when 5^100 is divided by 3?

View Question

If the length of a rectangle is doubled and the width is halved, what is the change in area?

View Question

The simple interest on Rs. 4000 at 5% per annum for 2 years is:

View Question

If a number is divisible by 9, it is also divisible by which of the following?

View Question

What is the value of log₃(27)?

View Question

If x + y = 10 and xy = 21, what is the value of x³ + y³?

View Question

A sum triples in 20 years at simple interest. What is the rate of interest per annum?

View Question

If a = 4 and b = 5, what is the value of (a+b)^2?

View Question