So you want another logarithm triangle (w/ law of cosines this time!) @blackpenredpen

So you want another logarithm triangle (w/ law of cosines this time!) @blackpenredpen

Uploaded March 2026 | Updated September 2026, 2 weeks ago

Answering a viewer's question today! Here's a triangle where the sides are ln(x), ln(2x), ln(3x), along with an angle we know, and using the law of cosines.
The logarithmic RIGHT triangle: youtu.be/CMdJPwEbE8A?si=3ncgwcOITTNScAj2
Law of cosines proof: youtu.be/843Uw-Hj-OQ?si=3pAxucAji-974Vpr

🛍 Shop my math t-shirts & hoodies: 👉 amzn.to/3qBeuw6
👉 Support this channel patreon.com/blackpenredpen

#blackpenredpen #calculus

So you want another logarithm triangle (w/ law of cosines this time!)

Is 1-1+1-1+1-1+...=1/2 really true?

How many square roots does the 2x2 zero matrix have?

Solving a deductive puzzle from Berkeley mini Math Competition

Volume of revolution (single integral vs triple integral)

Using Feynmans technique TWICE! (the integral of sin^3(x)/x^3 from 0 to inf)

when your calculus test has only one problem

Can you solve ln(x)+ln(-x)=0

Is this equation solvable? x^ln(4)+x^ln(10)=x^ln(25)

if your calculus teacher still doesnt believe the DI method...

5 Math Video Categories That Grew My Channel (12 Years on YouTube)

proving the limit of a product is the product of the limits, epsilon-delta definition

blackpenredpen |

So you want another logarithm triangle (w/ law of cosines this time!)