AP EAMCET202123 Aug 2021Evening ShiftMathematicsTrigonometric Ratios & IdentitiesActual
^2 5^ + ^2 10^ + ^2 15^ + + ^2 90^ is equal to
Options
- A8 1 2
- B9
- C9 1 2
- D4 1 2
Correct answer
C. 9 1 2
Step-by-step solution
^2 5^ + ^2 10^ + ^2 15^ + + ^2 90^ aligned ^2 5^ + ^2 10^ & + + ^2 45^ + ^2 50^ & + + ^2 80^ + ^2 85^ + ^2 90^ aligned aligned & ^2 85^ + ^2 80^ + + ^2 50^ + ^2 45^ & + ^2 50^ + + ^2 80^ + ^2 85^ + ^2 90^ aligned aligned & ( ^2 85^ + ^2 85^ )+ ( ^2 80^ + ^2 80^ ) & + + ( ^2 50^ + ^2 50^ )+ ^2 45^ + ^2 90^ aligned 1+1+ 1+ 1 2 +1=9 1 2