Question

if sinA=3/5 then what is cos A= ?

Answer 1

Step-by-step explanation:

SinA = O.s /h

sinA = 3/5

h²= o.s²+a.s²

5²= 3²+a.s²

25-9 = a.s²

16 = a.s²

a.s = 4

cos A = 4/5

Answer 2

GivEn:-

• SinA = $\dfrac{3}{5}$

To find:-

• CosA

Solution:-

We know that:-

★ Sin²A + Cos²A = 1

$\leadsto$ $\bigg( \dfrac{3}{5} \bigg)^2$ + cos²A = 1

$\leadsto$ $\dfrac{9}{25}$ + cos²A = 1

$\leadsto$ cos²A = 1 - $\dfrac{9}{25}$

$\leadsto$ cos²A = $\dfrac{25 - 9}{25}$

$\leadsto$ cos²A = $\dfrac{16}{25}$

$\leadsto\sf \sqrt{ \cos^2{A}} = \sqrt{ \bigg( \dfrac{16}{25} \bigg)}$

$\leadsto\sf \cos{A} = \sqrt{ \bigg( \dfrac{4}{5} \bigg)^2}$

$\leadsto {\underline{\underline{\boxed{\sf{\purple{ \cos{A} = \dfrac{4}{5}}}}}}}$

★ Hence Solved!!

$\rule{200}3$