161 - Mathematics Questions Answers
Sir/Madam,
Suddenly a question struck on my mind: 0×∞= 1 or 0?? as 1⁄0=∞.
it will be 0, assume it by considering that ∞ is a big number
for ex. 0*(1111111111111111111111111) = 0
Solve
tanx-3cotx=2tan3x(0<x<360)
cosx-sinx=cosy-siny
cos2xcotx+1=cos2x+cotx
tanx - 3/tanx = 2[3tanx-tan3x]/[1-3tan2x]
so [tan2x - 3]/tanx = 2tanx[3-tan2x]/[1-3tan2x]
so [tan2x - 3][1-3tan2x] = 2tan2x[3-tan2x]
so [tan2x - 3][1-3tan2x] + 2tan2x[tan2x-3] = 0
so [tan2x - 3][1-tan2x] = 0
so tanx = 1, -1, √3, -√3
now check the values satisfying last eq.
then put these values in 2nd eq. to get answer.
Find the value :-
(tan69 +tan66) / (1 - tan69.tan66)
use formula of tan(A+B)
Find the max. and min. value of
y = 7cosA + 24sinA
7cosA + 24sinA
= 25[7cosA/25 + 24sinA/25] = 25[cosAcosB + sinAsinB] where tanB = 24/7
= 25cos[A-B] max and min of cos[A-B] = 1 and -1
so max. = 25 and min. = -25
Prove that :-
tanA + 2tan2A + 4tan4A + 8cot8A = cosecA / secA
We have to prove
tanA + 2tan2A + 4tan4A + 8cot8A = cosecA / secA
or tanA + 2tan2A + 4tan4A + 8cot8A = cotA
or 2tan2A + 4tan4A + 8cot8A = cotA - tanA
or tan2A + 2tan4A + 4cot8A = [1-tan2A]/2tanA
or tan2A + 2tan4A + 4cot8A = cot2A
or 2tan4A + 4cot8A = cot2A - tan2A
or tan4A + 2cot8A = [1-tan22A]/2tan2A
or tan4A + 2cot8A = cot4A
or 2cot8A = cot4A-tan4A
or cot8A = [1-tan24A]/2tan4A
it is true so proved
Prove that :-
sin(A+B+C+D) + sin(A+B-C-D) + sin(A+B-C+D) + sin(A+B+C-D) = 4sin(A+B).cosC.cosD
sin(A+B+C+D) = sin(A+B)[cosCcosD-sinCsinD]+cos(A+B)[sinCcosD+cosCsinD]
similarly solve all the terms and add all these terms for getting answer
what will be the rank of word OPTION in the dictionary of words formed by letters of the word OPTION
OPTION
ordered way INOOPT
total words = 6!/2! = 360
so rank = (360/6)*2+([60*2]/5)*3+(24/4)*3+(6/3)*0+(2/2)*1+1 = 120+72+18+0+1+1 = 212
FIND DOMAIN OF f(x)=log4log3 log2x WHERE 4,3,2 ARE BASES ?
f(x)= log4log3log2x
so 0 < log3log2x < ∞
so 1 < log2x < ∞
so 2 < x < ∞
((1(secA.secA-cosA.cosA))-(1/(cosecA.cosecA-sinA.sinA))).sinA.sinA.cosA.cosA=(1-cosA.cosA.sinA.sinA)/(2+cosA.cosA.sinA.sinA)
Submit the correct question, In first bracket / will be there so
((1/(secA.secA-cosA.cosA))-(1/(cosecA.cosecA-sinA.sinA))).sinA.sinA.cosA.cosA
= [cos2A/sin2A(1+cos2A) - sin2A/cos2A(1+sin2A)]sin2Acos2A
= [cos4A(1+sin2A) - sin4A(1+cos2A)] / [(1+sin2A)(1+cos2A)]
now solve
if x is any real number and cosA=x^2+1/2x then cos A value is
x2+1 > 2x so cosA>1 which is not possible