defence exam ITBP (Telecommunication) Head Constable Mock Test 2024 Mathematics Trigonometry Trigonometric Ratios
If \(\cos \theta = \frac{8}{{17}}\) and θ lies in the first quadrant, then the value of cos (30 + θ) + cos (45 – θ) + cos (120 – θ) is
1
\(\frac{{23}}{{17}}\left( {\frac{{\sqrt 3 - 1}}{2} + \frac{1}{{\sqrt 2 }}} \right)\)
2
\(\frac{{23}}{{17}}\left( {\frac{{\sqrt 3 + 1}}{2} + \frac{1}{{\sqrt 2 }}} \right)\)
3
\(\frac{{23}}{{17}}\left( {\frac{{\sqrt 3 - 1}}{2} - \frac{1}{{\sqrt 2 }}} \right)\)
4
\(\frac{{23}}{{17}}\left( {\frac{{\sqrt 3 + 1}}{2} - \frac{1}{{\sqrt 2 }}} \right)\)