Q) The angle of elevation of the top of a tower from a point on the ground which is 30 m away from the foot of the tower, is 30°. Find the height of the tower. Ans: Let the tower be AB and its height be h Now in Δ ABC, tan 300 = […]
September 2023
Q) The length of the shadow of a tower on the plane ground is √3 times the height of the tower. Find the angle of elevation of the sun. Ans: Let the tower be AB and its shadow be AC and angle of elevation from point C be θ Given that AC = √3 x
Q) Show that the points (- 2, 3), (8, 3) and (6, 7) are the vertices of a right-angled triangle. Ans: Let’s plot these points on graph, we get: Step 1: Now for a Δ ABC to be an right angled triangle, required condition is: AB2 = AC2 + BC2 Step 2: Let’s calculate the
Q) If cos A + cos2 A = 1, then find the value of sin2 A + sin4 A. Ans: cos A + cos2 A = 1 cos A = 1 – cos2 A cos A = sin2 A…………. (i) Now, sin2 A + sin4 A = (sin2 A) + (sin2 A) 2 by substituting
If Cos A + Cos^2 A = 1, then find the value of Sin^2 A + Sin^4 A. Read More »
Q) If 4 cot2 45° – sec2 60° + sin2 60° + p = then find the value of p. Ans: VIDEO SOLUTION STEP BY STEP SOLUTION 4 cot2 45° – sec2 60° + sin2 60° + p = 4 (1)2 – (2)2 + 4 – 4 + + p = p = 0 Therefore,
If 4 cot^2 45° — sec2^ 60° + sin^2 60° + p = 3/4 then find the value of p. Read More »
Q) Prove that 2 + √3 is an irrational number, given that √3 is an irrational number. Ans: Let us assume that 2 + √3 is a rational number Let 2 + √3 = ; q ≠ 0 and p, q are integers √3 = Since, p and q are integers; Therefore p – 2q is
Prove that 2 + √3 is an irrational number, given that √3 is an irrational number. Read More »
Q) An aeroplane when flying at a height of 3000 m from the ground passes vertically above another aeroplane at an instant when the angles of elevation of the two planes from the same point on the ground are 60° and 45° respectively. Find the vertical distance between the aeroplanes at that instant. Also, find
Q) ABCD is a parallelogram. P is a point on side BC and DP when produced meets AB produced at L. Prove that: (i) (ii) (iii) If LP : PD = 2 : 3, then find BP : BC Ans: VIDEO SOLUTION STEP BY STEP SOLUTION (i) Since DC ǁ AB (and AL) Line CB
Q) Sides AB and AC and median AM of a Δ ABC are proportional to sides DE and DF and median DN of another Δ DEF. Show that Δ ABC ~ Δ DEF. Ans: Construction: Extend AM to A’ such that AM = A’M and extend DN to D’ such that DN = D’N Join
Q)Jaya scored 40 marks in a test getting 3 marks for each correct answer and losing 1 mark for each incorrect answer., Had 4 marks being awarded for each correct answer and 2 marks were deducted for each incorrect answer then Jaya again would have scored 40 marks. How many questions were there in the