10th Class Mathematics Introduction to Trigonometry Question Bank Introduction to Trigonometery

  • question_answer
    If\[\cos 9\alpha =\sin \alpha \]a and\[9\alpha <{{90}^{o}}\], what is the value of tan 5 a?

    A)  \[\frac{1}{\sqrt{3}}\]                    

    B)         \[\sqrt{3}\]  

    C)  1                            

    D)         \[\frac{1}{2}\]

    Correct Answer: C

    Solution :

     \[L.C.M.\] \[\frac{6}{14}and\frac{2}{7}\] \[\Rightarrow \] \[\frac{L.C.M.(6,2)}{H.C.F.(14,7)}=\frac{6}{7}\] \[\text{7}\times \text{13}+\text{13}=\text{1}0\text{4}=\text{23}\times \text{13}\] \[\therefore \] \[\text{7}\times \text{13}+\text{13}\] \[\therefore \] \[\text{224}=\text{12}0\times \text{1}+\text{1}0\text{4}\] \[\text{12}0=\text{1}0\text{4}\times \text{1}+\text{16}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner