A rational number is a number that can be written as the ratio of two integers (in fraction form). In math, integers and fractions are both generally called rational numbers.
Significant figures are all the digits from the first non-zero digit on the left to the last digit, used to reflect the measurement accuracy.
The hypotenuse is a concept unique to right triangles in geometry. It refers to the side opposite the right angle and is also the longest side of the triangle.
The remainder is the number left over when integer division doesn't divide evenly, and it has to be smaller than the divisor and can't be negative.
Slope is mainly used to measure how slanted a line is, and it has a direct relationship with the angle of inclination. Understanding this is important for grasping the concept. Simply put, the slope is a numerical representation of how much a line tilts relative to the x-axis, and it's usually represented by the letter k.
Cosine is a type of trigonometric function in math. Simply put, in a right triangle, it's the ratio of the length of a sharp angle's adjacent side to the length of the hypotenuse.
An oblique triangle is a triangle that doesn't have a right angle, including both acute and obtuse types.
Cosmology is a branch of astronomy that studies the overall structure, evolution, and origin of the universe. Its core content includes the standard model made up of dark energy and dark matter, and it reveals the large-scale features of the universe through observations and theory. This field combines physics, philosophy, and other areas, is based on general relativity, and relies on observational techniques like cosmic microwave background radiation and supernova redshift to test theoretical models.
Imaginary numbers are a special kind of number in math, used to represent the square root of negative numbers. The key is the imaginary unit i, which satisfies i² = -1. They combine with real numbers to form complex numbers, giving solutions to equations that couldn’t be solved before.