Question No. 25
Let A and B are two angles such that sinA + sinB = 1 and cosA + cos B = 0 then the value of (36cos2A + 24cos2B) is equal to
Answers
Step-by-step explanation:
Perimeter of trapezium = 104 m
Length of Non-parallel sides = 18 m and 22 m
Altitude = 16m
Area of Trapezium = 0.5 * (sum of parallel sides)*altitude ------ (1)
Sum of parallel sides = Perimeter - (sum of non-parallel sides) = 104 m - (18+22)m = 104-40 m = 64 m
From (1), Area of Trapezium = 0.5*64*16 = 512 m^2
Ans: Area of trapezium = 512 m^2
Step-by-step explanation:
Question : Prove that√5 is irrational.
Answer :
Let us assume that √5 is a rational number.
Sp it t can be expressed in the form p/q where p,q are co-prime integers and q≠0
⇒√5=p/q
On squaring both the sides we get,
⇒5=p²/q²
⇒5q²=p² —————–(i)
p²/5= q²
So 5 divides p
p is a multiple of 5
⇒p=5m
⇒p²=25m² ————-(ii)
From equations (i) and (ii), we get,
5q²=25m²
⇒q²=5m²
⇒q² is a multiple of 5
⇒q is a multiple of 5
Hence, p,q have a common factor 5. This contradicts our assumption that they are co-primes. Therefore, p/q is not a rational number
√5 is an irrational number
Hence proved