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oh. ok.

so for cos^4(2x)

the derivative would be

[cos²(2x)²]'=[2cos²(2x)]*[2cos(2x)]*[-sin(2x)][2]

=-8cos³(2x)sin(2x)

and the whole equation would be,

2y (dy/dx) = 8sin³(2x)cos(2x) - 8cos³(2x)sin(2x)

dy/dx = {8sin(2x)cos(2x)[sin²(2x)-cos²(2x)]} / 2y

... but how do i go further?

i am supposed to make the dy/dx = (-sin8x)/y

thanx a lot for the answer

**silvercity87**- Replies: 3

How do I find the derivative of

y^2=sin^4(2x)+cos^4(2x) ?

I know that for y^2, i have to use implicit differentiation.

But for sin^4(2x), is it like saying (sin^2(2x))^2??

So in a similar question that goes

"How many 7 digit even numbers less than 3 000 000 can be formed using all the digits 1,2,2,3,5,5,6?", the answer would be

3*5*4*3*2*1*2 divide by 2*2=180 right?

but the answer is 210

I'm confused

Thank you for the answers though!

But the number has to be odd as well :$

**silvercity87**- Replies: 6

The question goes:

How many 6-digit odd numbers less than 200 000 can be formed using the digits 1,1,2,2,3 and 5?

How do I solve this kind of question? can anybody help me please?!!!:

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