Question

if sin A is 4 upon 5, find the value of cos A​

Answer 1

Step-by-step explanation:

sint=45

. Angle t is not in Quadrant 1.cos2t=1−sin2t=1−16/25=9/25

cost=±3/5

Since t isn't in Quadrant 1, hence, it lies in Quadrant 2, and cos t is negative.cost=−3/5

Answer 2

$\sin(A) = \frac{4}{5}$

But;

$\sin( \theta) = \frac{opposite \: side}{hypotenuse}$

By pythagoras theorem;

${AB}^{2}={BC}^{2}+{AC}^{2}$

Here;

• AB is hypotenuse.
• BC is opp. side.
• AC is adjacent side.

${5}^{2}={4}^{2}+{AC}^{2}$

${AC}^{2}=25-16$

${AC}^{2}=9$

${AC}=3$

But;

$\cos(A) = \frac{adjacent \: side}{hypotenuse}$

$\therefore \boxed{ \color{orange}\cos(A) = \frac{3}{5} }$

HOPE THAT HELPS!!