A close-up, angled photograph captures a page from a white, blue-lined grid notebook containing handwritten Portuguese text and mathematical equations

A close-up, angled photograph captures a page from a white, blue-lined grid notebook containing handwritten Portuguese text and mathematical equations. The writing is primarily in blue ink, with some numerical calculations and annotations in a lighter gray ink. The content focuses on financial mathematics, specifically dealing with discount and interest rates. Visible elements include: * A heading in gray ink: "Taxa de desconto e queremos uma do juro" (Discount rate and we want one of the interest). * A timeline diagram drawn in blue ink, featuring a horizontal line with vertical markers labeled "0" and "1 ano / 12 meses" (1 year / 12 months), and a curved arrow indicating a period. * Problem "a)" with blue ink text: "tx desconto trimestral / op. financeira" (quarterly discount rate / financial operation). * Equations in gray ink: "id = 0,013 / 1-0,013 = 0,013171225" and "ia = (1 + dm)^4 - 1 = 5,373", with a small circled "4" and an annotation "-> para ser 12 meses" (to be 12 months). * Problem "b)" in blue ink text, partially visible: "tx juro quadrinestral / efetivo 2 / referente oo 2º ano do quad..." (quadrennial interest rate / effective 2 / referring to the 2nd year of the quad...). The page is resting on a light-colored, flat surface, possibly a desk, with a faint white object visible in the upper left corner, potentially another sheet of paper or a part of the notebook binding. No individuals are present in the image. The image itself does not contain any visual information to determine the specific city of Covilhã, Portugal.