# questions about Matrix using glm

hi guys! about matrix i have two question :dejection:
1- What is determent exactly

2- i know thi equation s if i have parent and child nodes

child’s new transform = parent’s transform * child’s transform

but what if i have Parent’s Transform and Child’s New transform
how to calculat child’s transform (old transform)

thank you

Please don’t post to multiple sub-forums, since your question is not specific to glm this is a better place for it than OpenGL Toolkits (e.g. GLUT, GLFW, GLM), thanks.

1. Please see Wolfram Mathworld or Wikipedia - or whichever sites your favorite search engine suggests

2. It is an equation so you can move terms to the other side by multiplying both sides with the multiplicative inverse of the term you want to move - keeping in mind that matrix multiplication is not commutative, so you need to multiply both sides of the equation from the same side:

``````
C1 =        P * C0  // multiply both sides from the left with P^-1 (the inverse of P)
P^-1 * C1 = P^-1 * P * C0  // P^-1 * P cancel by definition
P^-1 * C1 =            C0

``````

aha thank you so much
thank you for telling me this
“move terms to the other side by multiplying both sides with the multiplicative inverse of the term you want to move”
much appreciate it