Two stations due south of a leaning tower which leans towards the north are at distances a and b from its foot if α and β be elevation of these station from the tower, Prove that its inclination θ to be Horizontal is given by Cot θ = (b cot α - acot β)/b-a
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Q.If T1 , T2 , T3 .....Tn are consecutive terms of an AP then prove that 1/T1T2 + 1/T2 T3 +........ + (n-1)/T1 Tn
Q. Find The sum of 20 terms of the series 1^2 - 2^2 + 3^2 - 4^2 + 5^2 .......... In Triangle ABC, <ACB = 900 Þ <BCP = 900
So, In Triangle BPC: BC2 = BP2 – CP2 Now, In Triangle ABC, AB2 = AC2 + BC2 Þ AB2 = AC2 + BP2 – CP2 AB2 = AC2 – CP2 + BP2 AB2 = (AC - CP) (AC + CP) + BP2 AB2 = (AC - CP) (AP) + BP2 AB2 = (AC x AP - CP x AP) + BP2 AB2 = AC x AP + BP2 - CP x AP But, AP x CP = BP x PD (D APB ~ D CPB) AB2 = AC x AP + BP2 - BP x PD AB2 = AC x AP + BP(BP – PD) AB2 = AC x AP + BP x BD |