If cosP=17 and cosQ=1314 where P and Q both are acute angles.
Then the value of P-Q is
30°
60°
45°
75°
Step 1. Find the value of P-Q:
Given, cosP=17
⇒ sinP=1–149 ∵sin2A+cos2A=1
=4849=487
Similarly,
cosQ=1314
⇒sinQ=1–169196
=27196=2714
Step 2. Put the values of cosP,sinP,cosQ,sinQ in given expression, we get
cos(P–Q)=cosPcosQ+sinPsinQ=171314+4872714=1398+3698=(13+36)98=4998=12
∴P-Q=cos-112=60°
Hence, Option ‘B’ is Correct.