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If A,B,C,D are the angles of a quadrilateral, prove that `"cos"1/2(A+B)+"cos"1/2(C+D)=0`.

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ICSE-TRIGONOMETRICAL FUNCTIONS -Exercise 4(d)
  1. Find the values of theta lying between 0^(@) and 360^(@) when tan th...

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  2. Find the values of theta lying between 0^(@) and 360^(@) when sec th...

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  3. Find the values of theta lying between 0^(@) and 360^(@) when sin th...

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  4. Find the values of theta lying between 0^(@) and 360^(@) when tan th...

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  5. Find the values of theta lying between 0^(@) and 360^(@) when sin th...

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  6. Find the values of theta lying between 0^(@) and 360^(@) when costhe...

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  7. If 0^(@)lt theta lt 90^(@) and cos theta=(4)/(5) find the values of ...

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  8. If 0^(@)lt theta lt 90^(@) and cos theta=(4)/(5) find the values of ...

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  9. If 0^(@)lt theta lt 90^(@) and cos theta=(4)/(5) find the values of ...

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  10. If 0^(@)lt theta lt 90^(@) and cos theta=(4)/(5) find the values of ...

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  11. Find six angles for which sin theta=-(sqrt(3))/(2).

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  12. Find all the angles between 0^(@) and 720^(@) whose tangent is -(1)/(s...

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  13. Find the values of theta between 0^(@) and 360^(@) which satisfy the e...

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  14. Find the values of theta between 0^(@) and 360^(@) which satisfy the e...

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  15. If tan theta=0.4, when theta lies between 0^(@) and 360^(@), write dow...

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  16. If cosx^(@)=sin 200^(@), find the possible values of x between -180^(@...

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  17. If A,B,C are angles of a triangle, prove that cosC=-cos(A+B).

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

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  19. If A,B,C are angles of a triangle, prove that (tan (B+C)+tan(C+A)+ta...

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  20. If A,B,C,D are the angles of a quadrilateral, prove that "cos"1/2(A+B)...

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