Question

The value of $\frac{{\cos }^{3}20°-{\cos }^{3}70°}{{\sin }^{3}70°-{\sin }^{3}20°}$is

(a) $\frac{1}{2}$
(b) $\frac{1}{\sqrt{2}}$
(c) 1
(d) 2

Answer 1

We have to evaluate the value. The formula to be used,

So,

Now using the properties of complementary angles,

So the answer is