Radians

Part of a question from the June 2019 Pure Maths Paper 1;

a) Show that the x coordinates of the turning points of the curve y = 10(e^-0.25x)sinx satisfy the equation tanx = 4

To complete this question, you need to use radians mode instead of degrees mode. How do you recognise that in this case?

Basically every time we touch calculus, we will use radians.

For the most part, maths folks just use radians entirely, for the fact that "the arc length of the the sector with angle 1 radian is 1" is convenient.

Granted for this question, while I haven't scribble down anything, the problem of radian/degree measures shouldn't come up? We are not told to evaluate x anyway.

if the x in the trig part doesn’t have a ° then its radians

for example tan(x) is radians but tan(x°) is degrees

Basically every time we touch calculus, we will use radians.

For the most part, maths folks just use radians entirely, for the fact that "the arc length of the the sector with angle 1 radian is 1" is convenient.

Granted for this question, while I haven't scribble down anything, the problem of radian/degree measures shouldn't come up? We are not told to evaluate x anyway.

you'll need to use the product rule to differentiate y. And as soon as you differentiate sin x, you must use radians otherwise one term in dy/dx would have an annoying factor of pi/180 so you wouldn't end up with the required equation.