Find below the NCERT Exemplar problems and their solutions for Class 10 Mathematics Chapter, Introduction to Trigonometry and its Applications:

Exercise 8.4

Long Answer Type Questions (Q. No. 1-6)

Question. 3 The angle of elevation of the top of a tower from certain point is 30°. If the observer moves 20m towards the tower, the angle of elevation of the top increases by 15°. Find the height of the tower.

Solution.

Let AC be the h  metre high tower and B be the initial point from where angle of  elevation of the top of tower is observed.

Let after moving 20m towards tower, observer stands on point D with angle of elevation being 30^o +15^o = 45^o and x metres away from the foot of tower.

Question. 5 If sinθ  + 2cosθ = 1, then prove that 2 sinθ - cosθ = 2.

Solution.              

Question. 6 The angle of elevation of the top of a tower from two points distant s and t from its foot are

Solution.

Let AC be the h  metre high tower and θ and (90° – θ) be the angles of elevation for distances s and t respectively.

[As the two angles of elevation are given to be the complementary angles]