Q.

P and Q are acute angles such that P > Q. Then which of the following is definitely true

(i) sinP<sinQ(ii) tanP>tanQ(iii) cosP>cosQ (iv) cosP>sinQ

1 only (i)  
2 only (ii)  
3 (i) and (ii) both  
4 only (iv)  

Ans.

(2)

Given that P and Q are acute angles such that P > Q

Let P=60° Q=30°.Checking (i):We know that sinθ increases as θ increases  from  0° to 90°sin60°=32,sin30°=12sinQ<sinPThus (i) is not trueChecking (ii):We know that tanθincreases as θ increases  from  0° to 90°tanP>tanQHence (ii) is true.Checking (iii):We know that cosθ increases as θ increases  from  0° to 90°So (iii) is not true.Checking (iv):cosP=cos60°=12,sinQ=sin30°=12cosP=sinQ