Question 12

Evaluate: $$ \left(\frac{ sinĀ  47^\circĀ  } {cosĀ  43^\circ}\right)^2Ā  Ā + \left(\frac{ cosĀ  43^\circĀ  } {sinĀ  47^\circ}\right)^2 -Ā  4cos^2 45^\circĀ  Ā $$

Solution

$$ \left(\frac{ sin 47^\circ } {cos 43^\circ}\right)^2 + \left(\frac{ cos 43^\circ } {sin 47^\circ}\right)^2 - 4cos^2 45^\circ $$

Ā $$\Rightarrow \left(\frac{ sin 47^\circ } {cos (90 -47)^\circ}\right)^2 + \left(\frac{ cos 43^\circ } {sin (90 - 43)^\circ}\right)^2$$ - 4 $$\times$$ $$\left(\frac{1}{\sqrt{2}}\right)^2$$

$$\Rightarrow \left(\frac{ sin 47^\circ } {sin 47^\circ}\right)^2 + \left(\frac{ cos 43^\circ } {cos 43^\circ}\right)^2 - 2 $$ =Ā 1 + 1 - 2 = 0


Create a FREE account and get:

  • Download RRB Study Material PDF
  • 45+ RRB previous papers with solutions PDF
  • 300+ Online RRB Tests for Free

cracku

Boost your Prep!

Download App