By whom among the following personalities who lived in the White House is ‘Living History’ a famous book written?

If θ is a positive acute angle and cos² θ + cos⁴θ = 1, then the value of tan²θ + tan⁴θ is?

Evaluate, tan 17°  tan 32°  + tan 32°  tan 41°  + tan 41°  tan 17°  =?

Find the value of  `1/2`  cosec 10   -  `2/(cosec 70)`   ?

If 2y . cos θ - x . sin θ = 0 and 2x . sec θ - y . cosec θ = 3, what is the value of x² + 4y²?

cos A (sec A – cos A) (cot A + tan A) = ?

If √3 tan 2θ – 3 = 0, then find the value of tanθ secθ – cosθ where 0 < θ < 90°

The maximum value of 15 sin² θ + 8 cos² θ is