SSC CHSL 2021 PYQ — Question 57

SSC CHSL - 16 April 2021 - Shift 1 • Quantitative Aptitude • Q57

What is the value of sin33°cos57°+sec62°sin28°+cos33°sin57°+cosec62°cos28°tan15°tan35°tan60°tan55°tan75°?{{sin33°cos57°+sec62°sin28°+cos33°sin57°+cosec62°cos28°} \over tan15° tan35° tan60°tan55°tan75°}?

Show answer & explanation

Correct answer: B

Explanation

The correct answer is Option 2 i.e. 3{ \sqrt{3}}

Concept Used:

sin(90 - A) = cosA

tan(90 - A) = cotA

sec(90 - A) = cosecA

Explanation:

According to the given question,

sin33°cos57°+sec62°sin28°+cos33°sin57°+cosec62°cos28°tan15°tan35°tan60°tan55°tan75°{{sin33°cos57°+sec62°sin28°+cos33°sin57°+cosec62°cos28°} \over tan15° tan35° tan60°tan55°tan75°}

⇒ sin(90−57°)cos57°+sec62°sin(90−62°)+cos(90−57°)sin57°+cosec(90−28°)cos28°tan15°tan(90−55°)tan60°tan55°tan(90−15°){{sin(90 - 57°)cos57°+sec62°sin(90 - 62°)+cos(90 - 57°) sin57°+cosec(90 - 28°)cos28°} \over tan15° tan(90 - 55°) tan60°tan55°tan(90 - 15°)}

⇒ cos57°​​cos57°+sec62°cos62°+sin57°sin57°+sec28°cos28°tan15°cot55°tan60°tan55°cot15°{{cos57°​​cos57°+sec62°cos62°+sin57°sin57°+sec28°cos28°} \over tan15° cot55° tan60°tan55°cot15°}

⇒ ​​cos257°+1+sin257°+1tan60°{{​​cos^257°+1+sin^257°+ 1} \over tan60°}

⇒ 33{3 \over \sqrt{3}} = 3{ \sqrt{3}}

Hence the required answer is 3{ \sqrt{3}}.