Understand Sine Definition: Recognize that sin45∘ refers to the sine of a 45-degree angle.Sine is a trigonometric function that gives the ratio of the length of the opposite side to the length of the hypotenuse in a right-angled triangle.
Recall Special Triangle: Recall the special triangle for a 45-degree angle, which is an isosceles right triangle. In such a triangle, the sides opposite the 45-degree angles are equal, and the hypotenuse is 2 times longer than either of the other two sides.
Apply Sine Definition: Use the definition of sine in a right triangle.For a 45-degree angle, the sine is the ratio of the length of the side opposite the angle to the length of the hypotenuse.Since the triangle is isosceles, the side opposite the 45-degree angle is the same length as the adjacent side.
Calculate Sine of 45 Degrees: Calculate the sine of 45 degrees using the special triangle.The length of the side opposite the 45-degree angle is 1 (if we assume the sides to be 1 unit for simplicity), and the length of the hypotenuse is 2.So, sin(45∘)=hypotenuseopposite=21.
Rationalize Denominator: Rationalize the denominator to express the sine value in a more standard form.To rationalize the denominator, multiply the numerator and the denominator by 2.sin45=21×22=22.