Question

If Cos A = 1/2 then the value of
Cos A [Cos A - Sec A] is​

Answer 1

Ans: -3/4

Please mark me as brainliest

Answer 2

Given :-

$\bf \cos A = \dfrac{1}{2}$

To Find:-

Value of $\bf \cos A ( \cos A - \sec A)$

Solution :-

Before starting the question we shall know that ;

• $\bf \sec \theta = \dfrac{1}{\cos \theta}$

__________________________

Consider the value we have to find :-

$\quad \leadsto \quad \bf \cos A ( \cos A - \sec A)$

Apply the above identity ;

${: \implies \quad \sf \cos A \bigg( \cos A - \dfrac{1}{\cos A}\bigg)}$

Now put the value of $\sf \cos A$ ;

${: \implies \quad \sf \dfrac{1}{2} \bigg( \dfrac{1}{2} - \dfrac{1}{\dfrac{1}{2}}\bigg)}$

${: \implies \quad \sf \dfrac{1}{2} \bigg( \dfrac{1}{2} - 2 \bigg)}$

${: \implies \quad \sf \dfrac{1}{2} \bigg( \dfrac{1}{2} - 2 \bigg)}$

${: \implies \quad \sf \dfrac{1}{2} \bigg( \dfrac{1-4}{2}\bigg)}$

${: \implies \quad \sf \dfrac{1}{2} \bigg(- \dfrac{3}{2}\bigg)}$

${: \implies \quad \bf \therefore \quad \cos A ( \cos A - \sec A) = - \dfrac{3}{4}}$

Henceforth , The Required Answer is $\bf - \dfrac{3}{4}$ :D