A spherical balloon of radius r subtends angle 60° at the eye of an observer. If the angle of elevation of its centre is 60° and h is the height of the centre of the balloon, then which one of the following is correct?

What is the maximum value of sin 2x · cos 2x?

If x = e^t cos t and y = e^t sin t, then what is…

What is the derivative ofsin(ln x) + cos(ln x)with respect to x at x =…

If x + y = 20 and P = xy, then what is the maximum…

What is∫ dx / sec²(tan⁻¹ x)equal to?