PROVING IDENTITIES!!
qn?
the answer is a calculator
\[(\sin x + \cos x)(\tan x + \cot x) =\sec x + \csc x\]
Change to sin and cos then FOIL it out
Ok. We have - (sin x + cos x ) (sinx/cosx + cosx/sinx) (since tan x = sinx/cosx and cot x = cosx/sinx) => (sin x + cos x) (sin^2x + cos^2x/ sin x . cos x) => (sin x + cos x) ( 1/sin x. cos x ) (since sin^2x + cos^2x = 1) => (sin x + cos x)/sin x. cos.x Separating sin x, cos x in numerator with common denominator, sin x / sin x. cos x + cos x . / sin x cos x => 1/cos x + 1/sin x => sec x + csc x (since 1/cos x = sec x, 1/sin x = csc x) Proved
\[(\sin x + \cos x)(\frac{ \sin x }{ \cos x }+\frac{ \cos x }{ \sin x })\] \[(\sin x + \cos x)(\frac{ \sin ^2 x + \cos ^2 x}{ \cos x \sin x })\] \[(\sin x + \cos x)(\frac{ 1 }{ \cos x \sin x })\]
i got it....thank you all...
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