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Mathematics 10 Online
OpenStudy (anonymous):

find the greatest and least value of (sin^-1 x)^2+(cos^-1x)^2

OpenStudy (anonymous):

@ganeshie8

OpenStudy (nincompoop):

you'll get help if your face isn't that scary looking

OpenStudy (anonymous):

f'(x)=0 x=tan1

ganeshie8 (ganeshie8):

just an observation : max value occurs when x=+-1

ganeshie8 (ganeshie8):

boundaries. for min value we may have to differentiate. there seems to be no shortcut

OpenStudy (anonymous):

but in exam we have to write n show ,evt,4 marker question..we just cant write observation based answers ;/

ganeshie8 (ganeshie8):

ok, set f'(x) = 0 and find the critical points

OpenStudy (anonymous):

x=tan1

OpenStudy (loser66):

why do you set it =0?

OpenStudy (loser66):

after take derivative, set it =0 to get the critical points, but at the original input, you set the problem =0, why?

OpenStudy (anonymous):

so if the curve is parallel to x axis somewhere we can know the point and then observe it from its LHL and RHL

OpenStudy (anonymous):

i did it after taking derivative only

ganeshie8 (ganeshie8):

asin(x) = acos(x) x = 1/sqrt(2)

OpenStudy (anonymous):

http://www.wolframalpha.com/input/?i=differentiate+%28arcsinx%29%5E2%2B%28arccosx%29%5E2+ equate it to 0 now,same thing

ganeshie8 (ganeshie8):

thats ur oly critical point for the potential min/max

ganeshie8 (ganeshie8):

you need to check your function at below :- 1) x = 1/sqrt(2) 2) domain extremes (boundaries)

ganeshie8 (ganeshie8):

Max f = max{ f(1/sqrt(2), f(-1), f(1) } Min f = min{ f(1/sqrt(2), f(-1), f(1) }

OpenStudy (anonymous):

thanks!

ganeshie8 (ganeshie8):

np :)

ganeshie8 (ganeshie8):

one thing i wana point out asin/acos is NOT atan

OpenStudy (anonymous):

yes..:|

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