One Derivitive Problem & One Optimization Problem

1. Find the derivitive of 3x^2tan(x)/(sec(x))

I put ((6xtan(x))+sec^2(x)3x^2(sec(x))-(sec(x)tan(x))(3x^2tan(x)))/(sec^2(x))

Not sure where I messed up...

2. (1 pt) If a projectile is fired from ground level with initial velocity of 3775 ft/sec and an inclination angle https://webwork.math.uga.edu/webwork...144/char0B.png, and if air resistance can be ignored, then its range---the horizontal distance it travels---is about R=(1/16)02sinhttps://webwork.math.uga.edu/webwork...144/char0B.pngcoshttps://webwork.math.uga.edu/webwork...144/char0B.png

feet. What value of https://webwork.math.uga.edu/webwork...144/char0B.png (in radians) maximizes the range?

I do not know how to do this problem..