Given the complex number Z = b-2i (B is a real number), and Z2 − I is a real number. (1) find the complex number Z; (2) if the point corresponding to the complex number (Z + AI) 2 in the complex plane is in the fourth quadrant, try to find the value range of the real number a

Given the complex number Z = b-2i (B is a real number), and Z2 − I is a real number. (1) find the complex number Z; (2) if the point corresponding to the complex number (Z + AI) 2 in the complex plane is in the fourth quadrant, try to find the value range of the real number a

(1) ∵ z = b-2i, if Z2 − I = B − 2I2 − I = (B − 2I) (2 + I) (2 − I) (2 + I) = (2B + 2) + (B − 4) i5 is a real number, then B = 4. ∵ z = 4-2i; (2) ∵ (Z + AI) 2 = (4-2i + AI) 2 = 16 - (A-2) 2 + 8 (A-2) I, the corresponding point on the complex plane is in the fourth quadrant, ∵ 16 − (a − 2) 2 > 08 (a
English noun phrases
Not a hint did they drop as to how to carry out the plan.
Not in a sentence can only be used as an adverb. How can not a modify a noun? Can it be used as an adjective? What are the forms of a noun group?
Not a can modify a noun, not a thing is the object of drop,
They didn't leave any tips on how to carry out the plan
They didn't say anything about how to carry out the plan.
Not in advance and used with the auxiliary verb do (did) to indicate negation. Emphasis is a fixed sentence pattern, not a modifier noun
The ing and past and plural forms of the following words
begin
tell
bring
Buy
catch
feel
come
Eat
know
stand
find
Get
give
hear
See
Sit
teach
write
Put
grow
The past plural form
begin beginning began
tell telling told
bring bringing brought
buy buying bought
catch catching caught
feel feeling felt
come coming came
eat eating ate
know knowing knew
stand standing stood
find finding found
get getting got
give giving gave
hear hearing heard
see seeing saw
sit sitting sat
teach teaching taught
write writing wrote
put putting put
grow growing grew
Learn English well, there are verbs without plural form
Past tense: begining past tense: began past participle: begun
Past participle: told
Past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle
Past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle
The verb progressive: catching... Unfolding
Past tense: begining past tense: began past participle: begun
Past participle: told
Past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle
Past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle
Past participle: past noun plural: catches
Past participle: felt
Past tense: coming past tense: come past participle: come
Past tense: eat past tense: ate past participle: eat en
Past participle: known
Past tense: standing past tense: stock past participle: stock
Past participle: found
Past tense: getting past tense: got past participle: got, gotten
Past participle: given
The verb progressive: hearing past tense: hear past participle: hear
Past tense: see past tense: see past participle: see
Past participle: SAT
Past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle: past participle
Past participle: written
The past participle: put
The past tense: growing past tense: great past participle: growing up
What is plural? ~Where do verbs come from plural? ~
telling,told
bringing,brought
buying,bought
catching,caught
feeling,felt
coming,came
eating,ate
knowing,knew
standing,stood
I ^ 2 = - 1 - (I ^ 2) = 1 - 5 (I ^ 2) = 5 with root (√ - 5) I = √ 5
Left = (√ - 5) I = (√ 5) I ^ 2 = - √ 5
Right = √ 5, that is - √ 5 = √ 5. What's the matter? What's wrong with me
Open the root, and there are two results
a^2=b^2
Then a = ± B
It's the same for imaginary numbers
That is, x ^ 2 = - 1
Then x = ± I
The root of - 5 is ± I √ 5
Negative numbers can't be radical, so they don't exist (root - 5)
-The root of 1 can make I or - I
In fact, the problem is 1 = √ - (- 1) = I √ - 1 = I * I = - 1
Negative numbers can not carry out the same root operation as positive real numbers
The so-called √ - 1 = I is a kind of mark, or √ - 1 = - I
The differences between English nouns and noun phrases
Noun noun and noun phrase noun phrase can be subjects. What's the difference between them? How to distinguish them?
1. Noun phrase refers to a phrase composed of several nouns or nouns and their modifiers
2. Two or more nouns can be connected by equivalent conjunctions such as and to form noun phrases
Find the past tense of the verb: add ed at the end, add d at the end, remove y and add ied at the end, double write the last letter, add ed and change irregularly
Forget to say, ten each
I'm sorry
pick-picked kick-kicked count-counted paint-painted protect-protected fill-filled call-called turn-turned play-played look-lookedname-named promise-promised like-liked love-loved live-lived use-used p...
For example, kill killed study studied decided decided speak spoke spoke
ask asked
change changed
cry cried
stop stopped
make made
Plural title
If Z belongs to C, | Z | = 1 and the complex number W = Z ^ 2-I + 1, then the value range of | w | is_____
Find the process
Let z = cosa + Sina IW = (COSA + Sina I) ^ 2-I + 1 = (COSA) ^ 2 + 2cosasina I - (Sina) ^ 2-I + 1 = cos (2a) + 1 + [sin (2a) - 1] i|w | = √ [(COS (2a) + 1) ^ 2 + (sin (2a) - 1) ^ 2] = √ [(2cos (2a) - 2Sin (2a) + 3] = √ [2 √ 2cos (2a + π / 4) + 3] - 1 ≤ cos (2a + π / 4) ≤ 13-2 √
Find English phrases about activities
Go on a trip
Swimming
Go shopping
Have a walk
Have a picnic
Play basketball
Play football
The verb of adding ed to regular English verbs in the past tense
There are two kinds of regular and irregular changes in the past tense and past participle. 1) regular changes in the past tense and past participle
I want to confirm the answer
I've done a plural question, and I think the answer is strange. I hope the experts can help me to confirm the answer (list the process in the highest bar)
Let z = cos θ + isin θ, θ∈ [0, π], w = - 1 + I, and find the value range of | z-w |
What I do is [root (3-2, root 2, root 5]
Z = cos θ + isin θ ∈ [0, π], w = - 1 + i|z-w | = | (COS θ + 1) + (sin θ - 1) I | = √ [(COS θ + 1) ^ 2 + (sin θ - 1) ^ 2] = √ [3 + 2cos θ - 2Sin θ] = √ [3-2 √ 2Sin (θ - π / 4)] θ - π / 4 ∈ [- π / 4,3 π / 4], so sin (θ - π / 4) ∈ [- √ 2 / 2,1] so | Z ∈ [...]