Home
Class 9
MATHS
If cosec theta = sqrt2 , find the value...

If cosec ` theta = sqrt2 `, find the value of :
` (1)/(tan A ) +( sin A)/(1+ cos A) `

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we start with the given information that \( \csc \theta = \sqrt{2} \). ### Step 1: Understand the relationship of cosecant Cosecant is defined as the reciprocal of sine: \[ \csc \theta = \frac{1}{\sin \theta} \] Thus, if \( \csc \theta = \sqrt{2} \), we can find \( \sin \theta \): \[ \sin \theta = \frac{1}{\csc \theta} = \frac{1}{\sqrt{2}} = \frac{\sqrt{2}}{2} \] ### Step 2: Find cosine using the Pythagorean identity Using the Pythagorean identity: \[ \sin^2 \theta + \cos^2 \theta = 1 \] we can find \( \cos \theta \): \[ \left(\frac{\sqrt{2}}{2}\right)^2 + \cos^2 \theta = 1 \] \[ \frac{2}{4} + \cos^2 \theta = 1 \] \[ \frac{1}{2} + \cos^2 \theta = 1 \] \[ \cos^2 \theta = 1 - \frac{1}{2} = \frac{1}{2} \] \[ \cos \theta = \pm \frac{\sqrt{2}}{2} \] ### Step 3: Find tangent Tangent is defined as: \[ \tan \theta = \frac{\sin \theta}{\cos \theta} \] Using \( \sin \theta = \frac{\sqrt{2}}{2} \) and \( \cos \theta = \frac{\sqrt{2}}{2} \): \[ \tan \theta = \frac{\frac{\sqrt{2}}{2}}{\frac{\sqrt{2}}{2}} = 1 \] ### Step 4: Substitute values into the expression Now we need to evaluate: \[ \frac{1}{\tan A} + \frac{\sin A}{1 + \cos A} \] Substituting the values we found: \[ \frac{1}{1} + \frac{\frac{\sqrt{2}}{2}}{1 + \frac{\sqrt{2}}{2}} \] This simplifies to: \[ 1 + \frac{\frac{\sqrt{2}}{2}}{\frac{2 + \sqrt{2}}{2}} = 1 + \frac{\sqrt{2}}{2 + \sqrt{2}} \] ### Step 5: Simplify the second term To simplify \( \frac{\sqrt{2}}{2 + \sqrt{2}} \), we can rationalize the denominator: \[ \frac{\sqrt{2}}{2 + \sqrt{2}} \cdot \frac{2 - \sqrt{2}}{2 - \sqrt{2}} = \frac{\sqrt{2}(2 - \sqrt{2})}{(2 + \sqrt{2})(2 - \sqrt{2})} \] The denominator simplifies to: \[ (2 + \sqrt{2})(2 - \sqrt{2}) = 4 - 2 = 2 \] Thus, we have: \[ \frac{\sqrt{2}(2 - \sqrt{2})}{2} = \frac{2\sqrt{2} - 2}{2} = \sqrt{2} - 1 \] ### Step 6: Combine the terms Now we can combine the terms: \[ 1 + \left(\sqrt{2} - 1\right) = \sqrt{2} \] ### Final Answer Thus, the final value is: \[ \sqrt{2} \]
Promotional Banner

Topper's Solved these Questions

  • CHAPTERWISE REVISION (STAGE 3)

    ICSE|Exercise CO-ORDINATE GEOMETRY |6 Videos
  • CHAPTERWISE REVISION (STAGE 3)

    ICSE|Exercise GRAPHICAL SOLUTION|3 Videos
  • CHAPTERWISE REVISION (STAGE 3)

    ICSE|Exercise SOLIDS |6 Videos
  • CHAPTERWISE REVISION (STAGE 1)

    ICSE|Exercise Graphical solution |10 Videos
  • CIRCLE

    ICSE|Exercise EXERCISE 17(D)|12 Videos

Similar Questions

Explore conceptually related problems

If "cosec"theta=sqrt(2) ,then find the value of (tan^(2)theta-1) .

If sec A = sqrt2 , find the value of : (3 cos^2 A+5 tan^2A)/(4 tan^2 A - sin^2A)

If "cosec" theta = sqrt5 , find the value of : 2-sin^2theta - cos^2 theta

If cosec A = sqrt3 , find the value of: (2 sin ^(2)A + 3 cot ^(2) A)/( tan ^(2) A+ cos ^(2)A)

If "cosec" theta = sqrt(5) , find the value of (i) 2-sin^(2)theta - cos^(2)theta (ii) 2 + (1)/(sin^(2)theta) - (cos^(2)theta)/(sin^(2)theta)

If cos A = 0.5 and cos B = (1)/(sqrt2) , find the value of : (tan A - tan B)/( 1+ tan A tan B)

If costheta=(1)/(sqrt(2)) ,then find the value of (tan^(2)theta+1) .

If "cosec" theta = sqrt5 , find the value of : 2+1/(sin^2theta)-(cos^2theta)/(sin^2theta)

If sin theta = cos theta find the value of : 3 tan ^(2) theta+ 2 sin ^(2) theta -1

If cottheta=1/(sqrt(3)) , find the value of (1-cos^2theta)/(2-sin^2theta)

ICSE-CHAPTERWISE REVISION (STAGE 3) -TRIGONOMETRY
  1. A balloon is connected to a meteorological station by a cable of lengt...

    Text Solution

    |

  2. ABCD is an isosceles trapezium with AB parallel to DC, AD = BC = 12 cm...

    Text Solution

    |

  3. ABCD is an isosceles trapezium with AB parallel to DC, AD = BC = 12 cm...

    Text Solution

    |

  4. If A,B,C are angles of a triangle, prove that "tan "(B+C)/(2)="cot"...

    Text Solution

    |

  5. If A + B = 90 ^(@) , show that : cos A = sqrt(( cos A)/(sin B) -...

    Text Solution

    |

  6. Prove that : tan (55^(@) + x) = cot (35^(@) - x)

    Text Solution

    |

  7. Prove that : sec (70^(@) - 0) = cosec (20^(@) + 0)

    Text Solution

    |

  8. Prove that : Sin( 28 ^(@) +A) = cos ( 62 ^(@) - A)

    Text Solution

    |

  9. Prove that : (sinthetacos(90^0-theta)costheta)/(sin(90^0-theta))+(cost...

    Text Solution

    |

  10. If tan2theta=cot(theta+6^@) , where 2theta and theta+6^@ are acute a...

    Text Solution

    |

  11. If in Delta ABC , angle C = 90 ^(@) , prove that : sqrt((1-sin A)...

    Text Solution

    |

  12. Solve for theta (0^(@) lt theta lt 90 ^(@)) 2 sin ^(2) theta = (...

    Text Solution

    |

  13. Solve for theta ( 0 ^(@) lt theta lt 90^(@)) 2 cos 3 theta= 1

    Text Solution

    |

  14. If cosec theta = sqrt2 , find the value of : (1)/(tan A ) +( sin ...

    Text Solution

    |

  15. If 2 cos theta = sqrt3. prove that : 3 sin theta - 4 sin ^(3) thet...

    Text Solution

    |

  16. Given A is an acute angle and 13 sin A = 5 , evaluate : ( 5 sin A...

    Text Solution

    |

  17. Prove that cos 30 ^(@) = (sqrt3)/(2)

    Text Solution

    |

  18. If sin theta = cos theta find the value of : 3 tan ^(2) theta+ 2 si...

    Text Solution

    |

  19. IF cos B = (3)/(sqrt(13)) and A + B = 90 ^(@) find the value of s...

    Text Solution

    |

  20. Two opposite angles of a rhombus are 60° each. If the length of each s...

    Text Solution

    |