If cos θ1 = (1/2) ( x + (1/x)), cos θ2 = (1/2) (y + (1/y)) then cos(θ1 - θ2) equals

Question

If cos θ1 = (1/2) ( x + (1/x)), cos θ2 = (1/2) (y + (1/y)) then cos(θ1 - θ2) equals (A) xy + (1/xy) (B) (x/y) + (y/x) (C) (1/2)((x2 - y2/xy)) (D) None of these

Tardigrade Admin · Accepted Answer

Correct answer is (d) None of these

Q. If $cos θ_{1} = \frac{1}{2} (x + \frac{1}{x}), cos θ_{2} = \frac{1}{2} (y + \frac{1}{y})$ then $cos (θ_{1} - θ_{2})$ equals

$x y + \frac{1}{x y}$

$\frac{x}{y} + \frac{y}{x}$

$\frac{1}{2} (\frac{x ^{2} - y ^{2}}{x y})$

None of these

Correct answer is (d) None of these

Q. If cosθ1​=21​(x+x1​),cosθ2​=21​(y+y1​) then cos(θ1​−θ2​) equals

xy+xy1​

yx​+xy​

21​(xyx2−y2​)

None of these

Correct answer is (d) None of these

Q. If $cos θ_{1} = \frac{1}{2} (x + \frac{1}{x}), cos θ_{2} = \frac{1}{2} (y + \frac{1}{y})$ then $cos (θ_{1} - θ_{2})$ equals

$x y + \frac{1}{x y}$

$\frac{x}{y} + \frac{y}{x}$

$\frac{1}{2} (\frac{x ^{2} - y ^{2}}{x y})$