Figure 1. Answer on item number 15 written by a student from the experimental group (ES2) using sine of the sum of two angles formula

From

The Influence of Mathematical Communication on Students’ Mathematics Performance and Anxiety

Laila S. Lomibao, Charita A. Luna, Rhoda A. Namoco

American Journal of Educational Research. 2016, 4(5), 378-382 doi:10.12691/education-4-5-3