Question

show that the equation of normal at any point on the curve x=3 cos a - cos​3 a , y= 3 sin a - sin3a is 4(y cos3a - x sin3a)=3 sin(4a)?

Answer 1

Sin^2A+cos^2A=1. So given condition can be revised as (Sin A-cosA) (sin^2A+ cos^2A-sin A cos A).

Do the items. Answer will come. Be that as it may, I think there is some mix-up. Either first section term has + or second one positive. Both can't be negative.

The other term in the brackets, being second degree in wrongdoing An and cos A, recommends that that may be helpful.