====== Question 9, Review Exercise ====== Solutions of Question 9 of Review Exercise of Unit 09: Trigonometric Functions. This is unit of Model Textbook of Mathematics for Class XI published by National Book Foundation (NBF) as Federal Textbook Board, Islamabad, Pakistan. =====Question 9===== ** Solution. ** ====Go to ==== [[math-11-nbf:sol:unit09:Re-ex-p6|< Question 8 ]] [[math-11-nbf:sol:unit09:Re-ex-p8|Question 10(i-v) >]]