Question

✓ 1Q. If SinA=a/b then CosA=
(A)
Vo+a
b
(B)
b
(C) b/a
(D) a/b​

Answer 1

$\bigstar$ EXPLAINATION $\bigstar$

• Correct Question

If SinA = a/b then CosA = ??????

• Procedure

$\sin(A) = \frac{a}{b}$

We know that,

$Hypotenuse² = Perpendicular² + Base²$

Also,

$\sin(\theta) = \frac{Perpendicular}{Hypotenuse}$

Therefore,

We get to know that a is the perpendicular and b is hypotenuse

Let the base be x

$b²=a²+x²$

$x² = b²-a²$

$x = \sqrt{(b²-a²)}$

$\cos(\theta) = \frac{Base}{Hypotenuse}$

Therefore,

$\cos(A) = \frac{ \sqrt{(b²-a²)} }{b}$