Question

Find angle without using the concept of dot product. ​

Answer 1

ACIDS AND BASES NEUTRALISE EACH OTHER TO FORM CORRESPONDING SALTS AND WATER....

Answer 2

Answer:

${\tt{\green{\underline{\underline{\huge{Solution}}}}}}$

$Let the 2 vectors be (x1 y1) and (x2 y2) and the angle measured from the x-axis be a and b respectively with a > b. Therefore the angle between the 2 vectors, say c, is a - b.</p><p></p><p>c = a - b</p><p></p><p>The use the tangent angle sum formula</p><p></p><p>tan c = tan (a - b)</p><p></p><p>tan c = (tan a - tan b)/(1 + tan a · tan b)</p><p></p><p>tan a = y1/x1</p><p></p><p>tan b = y2/x2</p><p></p><p>tan c = ((y1/x1) - (y2/x2))/(1 + (y1/x1)(y2/x2))</p><p></p><p>tan c</p><p></p><p>= ((x2·y1 - x1·y2)/x1·x2)/((x1·x2 + y1·y2)/x1·x2)</p><p></p><p>tan c = (x2·y1 - x1·y2)/(x1·x2 + y1·y2)</p><p></p><p>c = arctan((x2·y1 - x1·y2)/(x1·x2 + y1·y2))</p><p></p><p>That's the formula</p><p></p><p>Hence that's the other way.</p><p></p><p>$