Railways Sample Paper RRBs Assistant Loco Pilot and Technician CBT STAGE-I Sample Paper-8

  • question_answer
    If \[\sec \alpha \,=\frac{5}{4},\]then \[\frac{\tan \alpha }{1+{{\tan }^{2}}\alpha }\]is equal to

    A)  \[\frac{9}{25}\]            

    B)  \[\frac{12}{25}\]

    C)  \[\frac{3}{4}\] 

    D)  \[\frac{1}{25}\]

    Correct Answer: B

    Solution :

    \[\therefore \] \[\sec \alpha =\frac{5}{4}\] \[\therefore \] \[\tan \alpha =\sqrt{{{\sec }^{2}}\alpha -1}\] \[=\sqrt{\frac{25}{16}-1}=\sqrt{\frac{25-16}{16}}=\sqrt{\frac{9}{16}}=\frac{3}{4}\] Now,\[\frac{\tan \alpha }{1+{{\tan }^{2}}\alpha }=\frac{3/4}{1+{{(3/4)}^{2}}}\] \[\,=\frac{3/4}{1+9/16}=\frac{3/4}{25/16}=\frac{12}{25}\]


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