If the segments joining the points `A(a , b)a n d\ B(c , d)` subtends an angle `theta` at the origin, prove that : `theta=(a c+b d)/((a^2+b^2)(c^2+d^2))`

If the segments joining the points A(a,b) and B(c,d) subtends an angle theta at the origin,prove that :theta=(ac+bd)/((a^(2)+b^(2))(c^(2)+d^(2)))

If the line segment joining the point A(a,b) and B(c,d) subtends an angle theta at the origin.Prove that cos theta=(ac+bd)/(sqrt((a^(2)+b^(2))*(c^(2)+d^(2))))

If the line segment joining the points A(a,b) and B(a, -b) subtends an angle theta at the origin, show that cos theta = (a^2 - b^2)/(a^2 +b^2) .

If the line segment joining the points A(a,b) and B(c,d) subtends an angle theta at the origin, then costheta is equal to

If the line segment joining the points A(a,b) and B (c, d) subtends a right angle at the origin, show that ac+bd=0

If the segment joining the points (a,b),(c,d) subtends a right angle at the origin,then

If a

If a sec theta-c tan theta=d and b sec theta+d tan theta=c ,then prove that (c^(2)+d^(2))^(2)-(ac-bd)^(2)=(ad+bc)^(2)

If a,b,c,d are in proportion then prove that sqrt((a^2+5c^2)/(b^2+5d^2))=a/b

If a, b, c, d are in G.P., then prove that: (b-c)^(2)+(c-a)^(2)+(d-b)^(2)=(a-d)^(2)