Q. 34.4( 191 Votes )

# If sin calculate Cos A and tan A

Answer :

Let ΔABC be a right-angled triangle, right-angled at point B

Given that:

As we know trigonometrical ratios give ratio between sides of right angled triangle instead of their actual values. So from sin A we get the ratio of Perpendicular and Hypotenuse of the triangle. Now as we don't know the exact value let Perpendicular = 3 k and Hypotenuse = 4 k

According to Pythagoras theorem: (Hypotenuse)^{2}= (Base)

^{2}+ (Perpendicular)

^{2}

Applying Pythagoras theorem in ΔABC, we obtain

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

(4*k*)^{2} = AB^{2} + (3*k*)^{2}

16*k ^{2}* - 9

*k*= AB

^{2}^{2}

7*k ^{2}* = AB

^{2}

Cos A =

= =

And we know thatTan A =

= =

So the ratios are cos A = √7/4 and tan A = 3/√7Rate this question :

Draw the graph of 2x – 3y = 4. From the graph, find whether x = -1, y = -2 is a solution or not. (Final)

NCERT - MathematicsIf , find the value of

RD Sharma - MathematicsIf , find the value of

RD Sharma - MathematicsIf , find the value of

If , find all other trigonometric ratios of angle

RD Sharma - MathematicsIf , find the value of

RD Sharma - MathematicsIf , find the value of

RD Sharma - MathematicsIf , show that

RD Sharma - MathematicsIf , find

RD Sharma - MathematicsIf , find the value of

RD Sharma - Mathematics