Question

Запишите теорему косинусов треугольнике ABC для сторон BC​

Answer 1

Ответ:

${BC}^{2} =AB^{2}+AC^{2}-2 \times AB \times AC \times cos(\alpha)$

Answer 2

The Cosine Rule for Triangle ABC and Side BC

The cosine rule, also known as the law of cosines, is a theorem that relates the lengths of the sides of a triangle to the cosine of one of its angles. In the case of triangle ABC, we can use the cosine rule to find the relationship between the lengths of the sides of the triangle and the cosine of angle A.

The cosine rule for triangle ABC, specifically for side BC, is as follows:

BC^2 = AB^2 + AC^2 - 2 * AB * AC * cos(A)

Where: - BC is the length of side BC - AB is the length of side AB - AC is the length of side AC - A is the angle opposite side BC

This formula allows us to calculate the length of side BC when we know the lengths of sides AB and AC, as well as the measure of angle A.

Please note that the formula can also be rearranged to solve for other variables, such as the angle A or the lengths of sides AB and AC, depending on the information given.

I hope this helps! Let me know if you have any further questions.