Express sin(5theta) in terms of sin(theta) and powers of sin(theta) only.

Consider the expression (cos(theta) + i*sin(theta))5 . (Where theta a real parameter).By De Moirve's theorem, we know this expression is equivalent to cos(5theta) + i sin(5theta).We can also apply the binomial expansion to this expression and sort into real and imaginary components.We can then equate these two expressions we have found and compare imaginary components to obtain the required solution.This is best written out by hand.

PF

Related Further Mathematics A Level answers

All answers ▸

Prove that 27(23^n)+17(10^2n)+22n is divisible by 11 for n belongs to the natural numbers


Use de Moivre’s theorem to show that, (sin(x))^5 = A sin(5x) + Bsin(3x) + Csin(x), where A , B and C are constants to be found.


Prove by induction that 11^n - 6 is divisible by 5 for all positive integer n.


Find the set of values of x for which (x+4) > 2/(x+3)