Question

if sin A=20/29 than find cos A. show stape by stape ans​

Answer 1

21/29

BTW It's 'step' not stape

Answer 2

Answer :

cos \thetaθ = \frac{21}{29}

29

21

It is easy to show the trigonometry functions as ratios which involves the sides of a right-angle triangle, whose sides are called the adjacent side, the opposite side and the hypotenuse marked as a, b and c respectively in the figure.

1. sine = sin \thetaθ = \frac{b}{c}

c

b

2. cosine = cos \thetaθ = \frac{a}{c}

c

a

3. tangent = tan \thetaθ = \frac{b}{a}

a

b

4. cotangent = cot \thetaθ = \frac{1}{tan\:\theta}

tanθ

1

5. secant = sec \thetaθ = \frac{1}{cos\:\theta}

cosθ

1

6. cosecant = cosec \thetaθ = \frac{1}{sin\:\theta}

sinθ

1

Given,

sin \thetaθ = \frac{20}{29}

29

20

= \frac{b}{c}

c

b

\implies a=\sqrt{c^{2}-b^{2}}⟹a=

c

2

−b

2

\implies\sqrt{29^{2}-20^{2}}⟹

29

2

−20

2

\implies\sqrt{441}⟹

441

\implies 21⟹21

Now, cos \thetaθ = \frac{a}{c}

c

a

= \frac{21}{29}

29

21