NDA2025MathematicsTrigonometric Ratios & IdentitiesActual
Consider the following for the three (03) items that follow: Let p = 35° , q = 25° and r = (-95°) . What is (p^2 + q^2 + r^2) equal to?
Options
- A1 2
- B1
- C3 2
- D2
Correct answer
C. 3 2
Step-by-step solution
Given p = 35^ , q = 25^ , and r = (-95^ ) . Simplifying r : r = - (90^ + 5^ ) = - 5^ We need to find the value of p^2 + q^2 + r^2 : p^2 + q^2 + r^2 = ^2 35^ + ^2 25^ + ^2 5^ Using the identities ^2 = 1 - 2 2 and ^2 = 1 + 2 2 : p^2 + q^2 + r^2 = 1 - 70^ 2 + 1 - 50^ 2 + 1 + 10^ 2 = 3 2 - 1 2 ( 70^ + 50^ - 10^ ) Using the sum-to-product formula C + D = 2 ( C+D 2 ) ( C-D 2 ) : 70^ + 50^ = 2 ( 70^ + 50^ 2 ) ( 70^ - 50^ 2 ) = 2 60^ 10^ = 2 ( 1 2 ) 10^ = 10^ Substituting this back into the expression: p^2 + q^2 + r^2 = 3