Question

If cosA=1/2,A lies in first quadrant,Find 3sinA-4tanA?

Answer 1

$cosa = 1 \div 2 \\ {ac}^{2} = {ab}^{2} + {bc}^{2} \\ {2}^{2} = {1}^{2} + {x}^{2} \\ x = \sqrt{3} \\ sina = \sqrt{3} \div 2 \\ tana = \sqrt{3} \\ 3sina - 4 tana = - 5 \sqrt{3} \div 2$
the answer is done by using Pythagoras theorem

Answer 2

Answer:

$cosA = 1 \div 2 \\ {ac}^{2} = {ab}^{2} + {bc}^{2} \\ {2}^{2} = {1}^{2} + {x}^{2} \\ x = \sqrt{3} \\ sinA = \sqrt{3} \div 2 \\ tanA = \sqrt{3} \\ 3sinA - 4 tanA = - 5 \sqrt{3} \div 2$